Apature

[Zeva]

So heres another nubbish question from me :P ... So i was wondering if lets say i have a 70-200mm f/2.8 lens what exactally does the appature on the camera do? isnt it fixed at f/2.8? thanks

[TheWengler]

You're right, that is newbish! :D f/2.8 is the max aperture which is available throughout the focal range. If you see something like f/3.5-5.6 then that means the max aperture is 3.5 at the wide angle end with a max of 5.6 at the telephoto end of the focal range.

[fionndruinne]

No, it isn't fixed at f/2.8, it's just the maximum aperture remains f/2.8. You can still "stop down" to smaller apertures (larger f/numbers).

Edit: Wengler beat me to it. And I was quick, I thought!

[SpecialK]

First off, the word is "aperture".

The aperture is the hole formed by the blades of the diaphragm of the lens. The actual size of the aperture is calculated by dividing the focal length by the f-number. The smaller the f-number, the larger the aperture and the more light it can let in at any given shutter speed. Depending on the lens, the maximum aperture can stay constant, or change to a larger f-number as the focal length increases. Large aperture/constant aperture lenses are the more expensiv versions.

[Zeva]

So... You mean like for the 17-70 sigma... its F/2.8-4.5 which means at 17ish its maxed at 2.8 and 70 its maxed at 4.5? so it cant go below 4.5 at 70 but like the 70-200 F/4 COULD go to f/4 at 70 AND 200? so its just the max? and its not fixed and can be shrunk? thanks BTW those were fast replies!

[TheWengler]

So... You mean like for the 17-70 sigma... its F/2.8-4.5 which means at 17ish its maxed at 2.8 and 70 its maxed at 4.5? so it cant go below 4.5 at 70 but like the 70-200 F/4 COULD go to f/4 at 70 AND 200? so its just the max? and its not fixed and can be shrunk? thanks BTW those were fast replies!

Yep, you got it.

[Zeva]

haha ty for help w/ nubbish question

[Razr]

So... You mean like for the 17-70 sigma... its F/2.8-4.5 which means at 17ish its maxed at 2.8 and 70 its maxed at 4.5?

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

[fionndruinne]

Uh... only at f/4.5, Razr. Not at f/2.8.

[zmikers]

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

Maybe I misread your post here but I think you are wrong. If you are in Av or M mode with a f/2.8-f4.5 lens on your camera and your Aperture is set at f/2.8, as you zoom the aperture will not stay at f/2.8, it cannot. It will change to match the max aperture to that specific focal length. So the sigma 17-70 f/2.8-4.5 has a max aperture of f/2.8 only at 17mm and a max aperture of f/4.5 at 70mm.

[Ray Schnoor]

So... You mean like for the 17-70 sigma... its F/2.8-4.5 which means at 17ish its maxed at 2.8 and 70 its maxed at 4.5? so it cant go below 4.5 at 70 but like the 70-200 F/4 COULD go to f/4 at 70 AND 200? so its just the max? and its not fixed and can be shrunk? thanks BTW those were fast replies!
Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.
Maybe I misread your post here but I think you are wrong. If you are in Av or M mode with a f/2.8-f4.5 lens on your camera and your Aperture is set at f/2.8, as you zoom the aperture will not stay at f/2.8, it cannot. It will change to match the max aperture to that specific focal length. So the sigma 17-70 f/2.8-4.5 has a max aperture of f/2.8 only at 17mm and a max aperture of f/4.5 at 70mm.
Zmikers is correct here. If you have a f/2.8-4.5 lens, you cannot change it to a f/2.8 lens just by putting it in Av or M mode. The max aperture changes throughout the focal range and the aperture value will change accordingly in both Av and M modes.

Ray.

[DonSchap]

Just so we're clear ... the numbers posted on the lens are the MAXIMUM (widest) aperture the lens can acheive. If the aperture is a sliding range, such as f/4-5.6 ... the MAXIMUM aperture of the lenses closes down as you ZOOM to a longer focal length.

If you set the camera to 70mm and f/4 aperture ... then zoom towards 300mm, the aperture begins to incrementally close down along the way ... to f/4.5 - f/5 - f/5.6 (somewhere around 235mm)

Doing this on a 18-200mm f/3.5-f/6.3 or an 18-70mm f/3.5-5.6 lens ... the effect is even more pronounced.

As the graph depicts:
30168

At the 40mm focal length, you can see that there is a heck of difference in max aperture between these two lenses, the 18-200 being the "brighter" of the two and therefore, a bit better for indoor use.

I hope this kind of helps. If not ... it's "book time" ... and get the camera out ... for a live demo. :D

[Razr]

Using any make/model of "Variable aperture" lens, set lens/camera body to the "A" (Av) function;
OR: put the camera body on full manual, which "disables" (disconnects both shutter and aperture automation from the camera body).

With either setting, the only way the aperture CAN BE CHANGED is manually: end of lesson.

C'mon guys, surely you know "full manual" operation means what it says? That NOTHING happens to the aperture or shutter unless the photographer makes it happen?

In "Av" mode, aperture automation is disabled thus (by definition) means "fixed aperture" .

Why argue with me when the Full manual and Av operational protocols define what will happen (or not)?

[D Thompson]

Using any make/model of "Variable aperture" lens, set lens/camera body to the "A" (Av) function;
OR: put the camera body on full manual, which "disables" (disconnects both shutter and aperture automation from the camera body).

With either setting, the only way the aperture CAN BE CHANGED is manually: end of lesson.

C'mon guys, surely you know "full manual" operation means what it says? That NOTHING happens to the aperture or shutter unless the photographer makes it happen?

In "Av" mode, aperture automation is disabled thus (by definition) means "fixed aperture" .

Why argue with me when the Full manual and Av operational protocols define what will happen (or not)?

Are you serious????

Take any zoom with a variable range and try to get the widest aperture at the longest zoom. It ain't gonna happen, that's why it's variable along the zoom range. The only variable zoom I have is Canon's efs 10-22 f3.5-f4.5. There is no way in any mode, av, manual, or whatever, that I'm gonna get f3.5 @ 22mm. It won't/can't happen. Let's take your thinking to primes - all I have to do is set mode to manual, choose f1.4 and my f2.8 suddenly gains that aperture? BS!

I think you are playing with words. I guess you could say that yes, the aperture is fixed along the variable zoom range :D:D. , but you still ain't gonna get the widest aperture at the longest zoom.

[fionndruinne]

Just you try setting your camera to manual, with a variable aperture zoom lens set at max aperture, at shortest focal distance, then zoom and see if your aperture stays at f/2.8. No such luck!

I'm... kinda surprised you don't already know this. But then... do you actually own a DSLR?

[Ray Schnoor]

Using any make/model of "Variable aperture" lens, set lens/camera body to the "A" (Av) function;
OR: put the camera body on full manual, which "disables" (disconnects both shutter and aperture automation from the camera body).

With either setting, the only way the aperture CAN BE CHANGED is manually: end of lesson.

C'mon guys, surely you know "full manual" operation means what it says? That NOTHING happens to the aperture or shutter unless the photographer makes it happen?

In "Av" mode, aperture automation is disabled thus (by definition) means "fixed aperture" .

Why argue with me when the Full manual and Av operational protocols define what will happen (or not)?
This quote from above just says it all: "C'mon guys, surely you know "full manual" operation means what it says? That NOTHING happens to the aperture or shutter unless the photographer makes it happen?"

The photographer makes it happen when he zooms the lens, thus changing the maximum aperture of a "variable maximum aperture" lens such as the Sigma 17-70 f/2.8-4.5 lens used as an example previously. Maximum aperture at 17mm = f/2.8, mamimum aperture at 70mm = f/4.5.

C'mon Razr, surely you know you can't make a lens aperture larger than its maximum value.

from Razr's quote: "Why argue with me when the Full manual and Av operational protocols define what will happen (or not)?"

Because changing a setting on a camera cannot change the makeup/physics of the lens. If it did, no one would ever buy those expensive 70-200 f/2.8 lenses. There would be no need.

Ray.

[JTL]

ROTFLMAO....

This is great! Pee-in-the pants funny! Way more entertaining than any current TV show or movie. More please!!! :D:D:D

[Prospero]

**The “pros”, me among them, generally use filters in that the proper filters do what filters are designed to do: modify incoming light in order to help balance exposures.
Better taking 20 seconds to spin on an ND or Polarizer filter than spending minutes per image post processing keepers.
Even better, our workflow is minimized whenever we use filters.

So, Razr, you count yourself among the pros, yet you don't understand the concept of a variable aperture lens ??? :eek:

I can understand where your confusion comes from. Take for instance the Sigma 70-300 f/4-5.6. If you were to use it with the aperture ring, you can set the ring at f/4 even when it is zoomed in to 300mm. However, the lens is then not really f/4 but f/5.6. The reason that the aperture ring does not show this is that the aperture ring is too small to fit the values for every range of focal lengths. Similarly, at 300mm you can stop down up to f/36 while the ring shows f/22.

If you were a newbie, your confusion would be understandable. But really, if you are a "pro" you should know better.... :rolleyes:

[Rooz]

lol funny stuff. obviously the 4/3rd's system, LEICA and OLYMPUS have devised a way to counteract this issue. us canon and nikon fans have to just suck eggs. lmao

[Razr]

Just you try setting your camera to manual, with a variable aperture zoom lens set at max aperture, at shortest focal distance, then zoom and see if your aperture stays at f/2.8. No such luck! That is only true if the aperture is still linked to the camera by electrical or physical connection.
I'm... kinda surprised you don't already know this. But then... do you actually own a DSLR? Yep: two of them: OLYMPUS E-500 & OLYMPUS E-510 and as soon as it ships, an OLYMPUS E-3.
All you guys have to do is tell me how, after you unlink (disable) the mechanical/electrical connection to the aperture, how then can an aperture "move" (closes down)?
*Remember, nearly all mechanical lenses are actuated by levers-etc.
Nearly every electrically actuated (CANON EOS for example) lens depends solely on the camera body connections for directions as to what shutter speed or aperture setting to use.
Break (disable) that/any connection to the aperture by setting "Av" or "M" on the body, you have TOTALLY IMMOBILZED the aperture.
When you are shooting in full manual for example, whatever aperture you set on the camera (the lens for manual lens) that is the only aperture you can use.
Take a PENTAX "M" or "K" mount lens for example: mount it on a PENTAX D10. Everything works between the two except autofocus. Why? No autofocus motor and/or electrical connections Disable the aperture by moving the lens off the “A” setting and now the aperture too is disabled.
The only way that aperture can then move is by hand (or dial with lenses with no aperture ring).
The same thing occurs when you break off the aperture tang on a PENTAX "KA2" lens. With no connection to the body, that lens remains wide open.
Take a CANON EOS body, mount an EOS lens then disable the electrical connection controlling the aperture (which is what the body does in Av mode) by setting the dial on "A".
Regardless of the focal length set on that disabled EOS lens, the aperture will not move (close down).

Let's try this: you have a train: you unlink the Caboose and then drive off: can (does) the Caboose ever move on its own? You have a chain: you cut the chain and drag the section left in your hand with you. Does the uncut chain move?
In other words, an aperture must have some sort of connection-electrical or mechanical, to the camera body before it can be actuated.

I think what all of you have failed to notice is any lens in Av mode on a battery driven body and/or in full manual setting on any type of body, the aperture is disabled and has no way to move on its own.

Here’s what mystifies me: in nearly every instance, everyone here knows when you mount a lens adapter to a camera body then mount any kind of zoom lens on the adapter, you have to use (by default) a fully open aperture, manually stopping down your shutter and aperture to obtain the correct exposure. Why? No connections to the camera body.

The same goes when you set a lens on the “Av” (aperture priority) setting: there is no connection (mechanical or elctrical) to the camera body.

[Rooz]

stop talking such complete and utter rubbish. max aperture is just that...MAXIMUM aperture. it cannot be changed regardless of what mode you shoot the camera in. no amount nonsense you try and use to justify your statement will change the fact that you're wrong. end of story.

[Razr]

lol funny stuff. obviously the 4/3rd's system, LEICA and OLYMPUS have devised a way to counteract this issue. us canon and nikon fans have to just suck eggs. lmao
Full manual (no connections to the body) nor Av operation (only the shutter is free to move) are not gender or brand specific.

All you have to tell me is: what happens to your aperture when you set your camera on "A" (Av) mode?
Does it (can it) close down?
And if your aperture can/does move in Av mode, please tell me how, since it has been immobilied by the camera (which is why they call it aperture priority?

That's the really LOL stuff, since your cameras can and do break the law of Av photography.

[Rooz]

of course it cannot be set wider than its max aperture. are you drunk ?

[tim11]

Maybe Razr can tell me how to set my Sigma F2.8 max to F1.0? ;)

[Razr]

Are you serious????

Take any zoom with a variable range and try to get the widest aperture at the longest zoom. It ain't gonna happen, that's why it's variable along the zoom range. The only variable zoom I have is Canon's efs 10-22 f3.5-f4.5. There is no way in any mode, av, manual, or whatever, that I'm gonna get f3.5 @ 22mm. It won't/can't happen.

I wonder why you guys cannot get over the word "variable". A variable aperture lens only functions that way when it is in full auto and shutter priority mode. Otherwise, in full manual or Av mode, the paerture is fixed. Let's take your thinking to primes - Let's not, since primes (by definition) are not, do not and cannot zoom, which make a dubious point moot. all I have to do is set mode to manual, choose f1.4 and my f2.8 suddenly gains that aperture? BS! Your question makes no cognitive sense. You posited an impossibility. I think you are playing with words. I guess you could say that yes, the aperture is fixed along the variable zoom range :D:D. , but you still ain't gonna get the widest aperture at the longest zoom. Think of it this way: when you set your body/lens on Av and zoom, what happens to the aperture?

Nothing: It's frozen in place: that's what "happens".
Instead, your shutter speed "varies" (to balance the exposure).
The opposite "happens" in "S" (Shutter priority) mode: your shutter is frozen in place while the aperture "varies" to balance the exposure.

Got it?

[achuang]

You've got to be kidding me, do you think the camera companies are lying to all of us? They say that the maximum aperture is f2.8-4.5 because it is just that. In aperture priority mode the the aperture is NOT locked in place. If I do it with my camera and put it at the widest aperture at wideangle, when i zoom in it does stop down. Mine goes from f3.5 at 18mm to f4.5 even in aperture priority mode. Just because you have removed the contacts which communicate with the body, the lens still has a physical limitation. that's why the constant aperture zooms cost so much. There was a thread like this a while ago, where a member thought that by using the aperture ring and shooting in manual mode that they were getting a faster aperture just because the aperture ring showed the max aperture value even when zoomed in. If I can find the post I will link it. But if you disable the camera control of the aperture by using the aperture ring and putting it on let's say the lens is 18-200 f3.5-6.3, put it on 200mm and f3.5 with the aperture ring. And try it the aperture controlled by the body where the max aperture at 200mm is f6.3 you will get the same shot that looks the same because you are not getting a faster shutter speed due to a larger max aperture.

[Rooz]

what on earth are you talking about ? if you have an f4-5.6 lens as you move into the higher end of the focal range where the maximum aperture is f5.6, it CANNOT be stopped down to f4. period.

doesn;t matter what mode you are in. the aperture on the camera adjusts itself to the maximum physically possible with that lens at that focal point without you even touching the aperture setting. even when not on the camera, so there is no electronic connection to anything, just look through the rear element of the lens and zoom in and out and you can see for yourself the "movement" in the blades in relation to the focal point.

i'm finding it hard to believe we're even talking about this. it may very well be the most ridiculous discussion in the history of this forum.

[D Thompson]

I wonder why you guys cannot get over the word "variable". A variable aperture lens only functions that way when it is in full auto and shutter priority mode. Otherwise, in full manual or Av mode, the paerture is fixed.

Then please tell me why my efs 10-22 f3.5-4.5 will only open to f4.5 @ 22mm? Yes, I can set the 20D to AV or M and it does not matter. f4.5 @ 22mm is it bud. I cannot set the aperture to f3.5 @ 22mm. Is this a factory defect? :D

Let's not, since primes (by definition) are not, do not and cannot zoom, which make a dubious point moot. Your question makes no cognitive sense. You posited an impossibility.

What does zoom have to do with it since there is no connection. A lens is a lens and as long as the camera is set to AV or M it shouldn't matter going by what you say. And speaking of posting an impossibility!:rolleyes:

Think of it this way: when you set your body/lens on Av and zoom, what happens to the aperture?

Nothing: It's frozen in place: that's what "happens".
Instead, your shutter speed "varies" (to balance the exposure).
The opposite "happens" in "S" (Shutter priority) mode: your shutter is frozen in place while the aperture "varies" to balance the exposure.

OK, we agree on how AV & TV work. :eek: But you still can't get f3.5 @ 22mm on my lens. For that matter, any other variable zoom you cannot get the widest aperture at the longest zoom. Will not, can not, and does not happen. Got it?

Got it?

I think most of us here have it, we're just waiting for you to get it.

[tim11]

----

All you have to tell me is: what happens to your aperture when you set your camera on "A" (Av) mode?
Does it (can it) close down?
And if your aperture can/does move in Av mode, please tell me how, since it has been immobilied by the camera (which is why they call it aperture priority?

That's the really LOL stuff, since your cameras can and do break the law of Av photography.

This is madness.... I won't be reading this thread anymore and this is my last input.
Take the f2.8-4.5 lens as an example, and in Av or S mode you put it to max F2.8. Then on full zoom of course the aperture can close down to 4.5.

One thing can interfere with the law of photography: The law of PHYSICS, ie. Lens design.

[Razr]

(SNIP) The photographer makes it happen when he zooms the lens, thus changing the maximum aperture of a "variable maximum aperture" lens Certainly not a true statement with a manual lens, and most difintiely not true when a lens is set on an aperture in Av mode. such as the Sigma 17-70 f/2.8-4.5 lens used as an example previously. Maximum aperture at 17mm = f/2.8, mamimum aperture at 70mm = f/4.5. True only if the lens is set on shutter priority or "P". Not true if set on Av or M. C'mon Razr, surely you know you can't make a lens aperture larger than its maximum value. Where did I say or infer such? Quote please. from Razr's quote: "Why argue with me when the Full manual and Av operational protocols define what will happen (or not)?"

Because changing a setting on a camera cannot change the makeup/physics of the lens. If it did, no one would ever buy those expensive 70-200 f/2.8 lenses. There would be no need.

Ray.The "physical makeup of the lens" is the elements, construction and lens openings. Only the shutter/aperture or both "change" to balance the exposure.
Though when you inject and set the light modifiers, the light values that strike the sensor/film do change.

And the physics say if there is no shutter/aperture, light passing through the lens (light tube) is a constant.

[SpecialK]

Never argue with a fool. This is even better than the "4/3's is its own form- factor" thread.

[fionndruinne]

Is it bad that I find this hilarious?

Razr, assuming you do own the DSLRs you name, how about moseying over to wherever you keep them and popping a variable aperture lens on one, setting it to your precious aperture-priority or manual mode, and checking it for yourself? No doubt you'll feel violated when your f/2.8 aperture setting somehow breaks the "law of Av photography" (just where did that law originate?:rolleyes:) by changing on its own to f/4.5. Then again, better not, since you may be freaked out by your apparently possessed camera, and sustain a heart attack.

i'm finding it hard to believe we're even talking about this. it may very well be the most ridiculous discussion in the history of this forum.

Amen to that, brother. Which is why it is so appealing.:D

[Razr]

This is madness.... I won't be reading this thread anymore and this is my last input.
Take the f2.8-4.5 lens as an example, and in Av or S


Which tells me me you are unaware that "S" (shutter priority) freezes the shutter and allows/forces the aperture to balance the exposure.
And "A" (Av) freezes the aperture, forcing the shutter to balance the exposure. mode you put it to max F2.8. Then on full zoom of course the aperture can close down to 4.5. Only if in "P" or "S" modes. Otherwise, in Av and full manual mode, the aperture (by defintion in those modes) is locked in place.

One thing can interfere with the law of photography: The law of PHYSICS, ie. Lens design.The "lens design" is merely a tube with glass optics that allow light to pass through, whereupon the light is modifed by shutter/aperture/timer settings.

[Rooz]

Certainly not a true statement with a manual lens, and most difintiely not true when a lens is set on an aperture in Av mode. True only if the lens is set on shutter priority or "P". Not true if set on Av or M.

it doesn't matter if it is a manual lens or not. just like it doesn;t matter if its in Av or M mode.

Where did I say or infer such? Quote please. .

you just said it in the exact same post. you've been saying it from the beginning and its WRONG.

[Razr]

Is it bad that I find this hilarious?


Amen to that, brother. Which is why it is so appealing.:D

Razr is not the thread topic.

[fionndruinne]

Ahh, but Razr is the only one I know of who can purvey just such a topic as this.:p

And you'll notice that everything in my post but what you quoted was on topic.

[Razr]

of course it cannot be set wider than its max aperture. are you drunk ?Please post the exact statement and post# where I said so.

Of course you won't find it.

[Rooz]

Which tells me me you are unaware that "S" (shutter priority) freezes the shutter and allows/forces the aperture to balance the exposure.
And "A" (Av) freezes the aperture, forcing the shutter to balance the exposure. Only if in "P" or "S" modes. Otherwise, in Av and full manual mode, the aperture (by defintion in those modes) is locked in place. The "lens design" is merely a tube with glass optics that allow light to pass through, whereupon the light is modifed by shutter/aperture/timer settings.

the lens has no bearing on the shutter speed so it's not relevant in the slightest to this discussion.

if the lens is just a tube with some glass in it what regulates the amount of light passing from the front of the lens to the rear element and ultimately the camera ? ie: where exactly are the aperture blades located ? or is that just an electronic figment of our imagination ? :rolleyes:

you simply cannot admit your wrong which makes you so much more foolish.

[Rooz]

Please post the exact statement and post# where I said so.

Of course you won't find it.

every post you've made makes that statement.

[achuang]

every post you've made makes that statement.

That's right. Saying that a 17-70 f2.8-4.5 lens can be shot at f2.8 at 70mm is saying that the lens can be shot wider than it's maximum aperture.

[Rooz]

and there lies the problem. apparently razr doesn;t recognise that a variable aperture lens actually has a variable max aperture according to its focal length. :rolleyes:

just for kicks though...

A variable aperture lens only functions that way when it is in full auto and shutter priority mode. Otherwise, in full manual or Av mode, the paerture is fixed.

[achuang]

Full manual (no connections to the body) nor Av operation (only the shutter is free to move) are not gender or brand specific.

All you have to tell me is: what happens to your aperture when you set your camera on "A" (Av) mode?
Does it (can it) close down?
And if your aperture can/does move in Av mode, please tell me how, since it has been immobilied by the camera (which is why they call it aperture priority?

That's the really LOL stuff, since your cameras can and do break the law of Av photography.

If you are unable to change your aperture in Av mode then there's something wrong with your camera. Aperture priority mode is the mode that allows you to be able to change your aperture and the camera decides on the shutter speed. Your camera seems to be the only one that can break what is called aperture priority. It's aperture priority because the photographer chooses the aperture suited for a particular photograph to give a suitable depth of field.

[tim11]

maybe just one more post.... :D
Maybe RAZR doesn't know what the discussion is all about?
Of course he keeps implying that the lens can be shot wider than it's maximum aperture.

On the other hand, what kind of camera/lens RAZR is using? I want to get one too so I can set to infinity aperture. :D

[Razr]

what on earth are you talking about ? if you have an f4-5.6 lens as you move into the higher end of the focal range where the maximum aperture is f5.6, it CANNOT be stopped down to f4. period. Your turn: post my exact quote and post#/page# where I said anything like what you just inferred. doesn;t matter what mode you are in. the aperture on the camera adjusts itself to the maximum physically possible with that lens at that focal point without you even touching the aperture setting. even when not on the camera, so there is no electronic connection to anything, just look through the rear element of the lens and zoom in and out and you can see for yourself the "movement" in the blades in relation to the focal point.
I took time to do what you suggested with my EOS, Pentax, & Oympus autofocusing lenses, all of which are zombified paperweights without the needed electrric stimulation.
Nearly all my manual focus lenses are physically actuated by electric pulses inside the body ([I]excepting my K-1000 that gets along just fine withoutr batteries[/w]!) being sent to actuating arms. In the case of my Pentax "M" and Canon "FD" lenses, you can zoom all day an absolutely nothing happens to the aperture setting.
i'm finding it hard to believe we're even talking about this. it may very well be the most ridiculous discussion in the history of this forum.That may be in large part because you and a few other sdon't know anything about the internal workings of SLR cameras...

[fionndruinne]

All Razr needs to do is pop a variable max-aperture on a body and try it, as I suggested.

Man, if only a 17-70mm which was really f/2.8 across the full range cost as little as that Sigma does... I kinda like Razr's idea, I think I'll go with it for the sake of daydreaming.

[Rooz]

Your turn: post my exact quote and post#/page# where I said anything like what you just inferred. ...

i'm not INFERRING anything. i'm TELLING you thats exactly what you've been saying and here's just ONE of many times where you have said the above.

http://www.dcresource.com/forums/showpost.php?p=260302&postcount=25

mate your trying to squirm your way out of this and all of us know you can't. admit you're wrong and just let it be.

maximum aperture in a variable aperture lens like say the sigma f4-5.6 will change throughout the focal range and there is NOTHING that can be done to alter that.

[achuang]

Your turn: post my exact quote and post#/page# where I said anything like what you just inferred.
I took time to do what you suggested with my EOS, Pentax, & Oympus autofocusing lenses, all of which are zombified paperweights without the needed electrric stimulation.
Nearly all my manual focus lenses are physically actuated by electric pulses inside the body ([I]excepting my K-1000 that gets along just fine withoutr batteries[/w]!) being sent to actuating arms. In the case of my Pentax "M" and Canon "FD" lenses, you can zoom all day an absolutely nothing happens to the aperture setting. That may be in large part because you and a few other sdon't know anything about the internal workings of SLR cameras...

Do you know of the Canon 100mm macro lens? Well any macro lens really. The higher the magnification and the closer the subject the greater the light fall off. So a f2.8 macro lens like the canon is 2.8 when focused at infinity, but when focused closer it slowly becomes close to f5 when at 1:1 magnification. From what I've heard the canon lens still says f2.8 even though it really is at f5 or around there but the camera adjusts for that. Just because the older technology doesn't have the ability to tell what the max aperture is at a given focal length, the aperture still has a limit to how wide it can go. Let's say the aperture is any random width, say 15mm wide at 17mm focal length. If this is a constant aperture zoom lens then the aperture size must actually get larger as you zoom in since the longer the focal length the larger the aperture size must be. Why do you think the expensive telephotos are so large. If the aperture stays at 15mm all the way until 70mm, then it is a much smaller f/stop than when at 17mm. If you have somehow gotten a camera that defies the laws of physics then please let us know.

[Razr]

maybe just one more post.... :D
Maybe RAZR doesn't know what the discussion is all about? I know it is not about Razr.
Of course he keeps implying that the lens can be shot wider than it's maximum aperture. I never said, inferred or "implied" anything remotely like what you’ve again l*ed about.
It is still incumbent on you to post where and when I said something even remotely related to what you "inferred"; again.
Quote please? On the other hand, what kind of camera/lens RAZR is using? I want to get one too so I can set to infinity aperture. :DAgain as you wrongly infer what I said, you owe me and this forum an answer to my pointed question(s):
where did I say what you inferred above?
and this thread is not about Razr.

[Ray Schnoor]

The photographer makes it happen when he zooms the lens, thus changing the maximum aperture of a "variable maximum aperture" lens.

Certainly not a true statement with a manual lens, and most difintiely not true when a lens is set on an aperture in Av mode.
Certainly true for any variable maximum aperture lens, manual or otherwise.

such as the Sigma 17-70 f/2.8-4.5 lens used as an example previously. Maximum aperture at 17mm = f/2.8, mamimum aperture at 70mm = f/4.5.

True only if the lens is set on shutter priority or "P". Not true if set on Av or M.

OK, lets try a different lens. I can't wait to see your answer for this one.

Example: Canon EF 70-300mm f/4.5-5.6 DO IS USM

In lenses, we can find the diameter of the aperture by this equation. Diameter = focal length / f#. In the above lens, at 70mm the maximum aperture diameter = 70mm/4.5 = 15.5mm and at 300mm the maximum aperture diameter = 300mm/5.6 = 53.6mm. Now under your assumption at 300mm in Av(aperture priority mode) the maximum aperture diameter = 300mm/4.5 = 66.7mm. Looking at the specifications for this lens on the Canon website, though, this lens takes a 58mm filter. That seems to be a tad bit smaller than the aperture size. Wonder how that can work?

Ray.

[Rooz]

I took time to do what you suggested with my EOS, Pentax, & Oympus autofocusing lenses, all of which are zombified paperweights without the needed electrric stimulation.
Nearly all my manual focus lenses are physically actuated by electric pulses inside the body ([i]excepting my K-1000 that gets along just fine withoutr batteries[/w]!) being sent to actuating arms. In the case of my Pentax "M" and Canon "FD" lenses, you can zoom all day an absolutely nothing happens to the aperture setting. That may be in large part because you and a few other sdon't know anything about the internal workings of SLR cameras...

no, you obviously didn;t becasue you seem to be the only person on the face of the planet that is able to achieve this phenomenon.

[tim11]

I know it is not about Razr. I never said, inferred or "implied" anything remotely like what you’ve again l*ed about.
It is still incumbent on you to post where and when I said something even remotely related to what you "inferred"; again.
Quote please? Again as you wrongly infer what I said, you owe me and this forum an answer to my pointed question(s):
where did I say what you inferred above?
and this thread is not about Razr.
You are getting more foolish every post you make. Read every post you made and see what I 'infered'. Maybe you are the only one foolish enough not to see that.

[Rooz]

prove us and the whole photographic world wrong and post a photo with this new miraculous discovery of yours with the full exif. woops...thats right...i forgot...you a PRO who is too good to post photos for us plebs to look at. :rolleyes:

[tim11]

I don't think RAZR can be serious. More likely he is trolling people to quote his nonsense. Anyone else has this impression?
Anyway... this thread (not about Razr) has to be voted thread of the month for a laugh.

Right now, he is testing his Pentax, Canon, Nikon, Panasonic systems with various lenses and showing us his professional scientific results at the same time. Go figure. :D

[achuang]

Think of it this way: when you set your body/lens on Av and zoom, what happens to the aperture?

Nothing: It's frozen in place: that's what "happens".
Instead, your shutter speed "varies" (to balance the exposure).
The opposite "happens" in "S" (Shutter priority) mode: your shutter is frozen in place while the aperture "varies" to balance the exposure.

Got it?

I think this is the problem that Razr has understanding. He thinks that when it's in Av that the aperture is stuck in place and that we can't change it. And that the opposite happens in shutter priority mode where the shutter is "frozen" in place while the aperture "varies" as he calls it. This varying of the aperture is not the same as a variable aperture lens.

[Rooz]

He thinks.

given the content of this thread, thats a pretty presumptuous statement wouldn;t you say ? :p

[Prospero]

Razr, you really don't have a clue what you are talking about.

The maximum f-stop of a lens - in other words, the maximum relative aperture of a lens - is in fact a fraction. With simple lenses, the f-stop can be used to calculate the physical size of the maximum aperture of a lens.

The following formula applies for simple lenses (i.e. one element and an aperture curtain):

aperture diameter = focal length / f-stop

With modern lenses, which are made up of multiple elements, this is no longer valid. The focal length which must be taken into account depends on the position of the apperture curtain with respect to the various elements. Still, the formula helps to get a basic idea of lenses (which you obviously lack).

With zoom lenses, the maximum aperture diameter is fixed. The lens does not automatically stop down when you zoom in. If you take a look at the Sigma 70-300, for instance, you will see that at 300mm the physical aperture is the same as at 70 mm. However the lens is not a fixed aperture lens, it is f/4-5.6.

Why is that? When you zoom in, you increase the focal length of a lens, in this case from 70 to 300. Since the maximum apperture stays the same it follows from the above formula that the f-stop of the lens must increase.

If you think about it, this is logical. If you make the angle from which you can capture light smaller, you will get less light if the size of the diaphragm stays the same.

So, to make a long story short. If you zoom in, the physical aperture stays the same, but the amount of light that will reach the sensor will decrease. Hence, the f-stop will be smaller.
Putting your camera in the full manual mode, in apperture priority or using it entirely manual with the aperture ring does not matter.

EDIT: I started typing this two hours before actually posting it, I was away from the computer in the meantime. This is why I said lots of things that had been said before (they hadn't been posted yet when I started typing). My appologies for that.

[achuang]

given the content of this thread, thats a pretty presumptuous statement wouldn;t you say ? :p

Point taken, I don't think i'll be posting on this thread. I have to go off to an exam now anyway. maybe i'll try Razr's method of taking photos when I go take pictures of my sister's newborn.

[Razr]

Do you know of the Canon 100mm macro lens? Well any macro lens really. The higher the magnification and the closer the subject the greater the light fall off. [/quote] the aperture still has a limit to how wide it can go. Why do you guys keep repeating that asinine conclusion when in fact, I have never mentioned such? Let's say the aperture is any random width, say 15mm wide at 17mm focal length. If this is a constant aperture zoom You’ve already segued off topic. The topic is not constant aperture zoom(s) but does aperture priority lock the aperture in place no matter what: at least that is my thesis. lens then the aperture size must actually get larger as you zoom in since the longer the focal length the larger the aperture size must be. Again, since you gave no aperture value, your argument fails for its lack of merit. Why do you think the expensive telephotos are so large. If the aperture stays at 15mm all the way until 70mm, then it is a much smaller f/stop than when at 17mm.You are free to mumble that Mantra all you want: it’s wrong, particularly so when you fail to note what mode/setting your camera is in. If Av (Aperture priority), the aperture (regardless of setting) is locked down tight and cannot move (open or close). Disprove my thesis by demonstrating how the aperture is not fixed in place in Av and M modes.

[SpecialK]

Please post the exact statement and post# where I said so.

Of course you won't find it.

---->>"The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range."

You've implied it here. Others have repeatedly argued that the lens will not be f2.8 over the entire range which your statement implies. You have never clarified your statement. But the lens will be constant aperture as you say, at f4.5 (minimum aperture at maximum zoom), but that is hardly "fast".

Added: You apparently have "aperture" and "f-stop" confused. You set the "f-stop" on your dial or ring. Because f-stop = focal length/aperture, as the focal length increases, the aperture must increase to keep the constant f-stop - which might have been what you meant, but not what you've said, repeatedly.

[Prospero]

Actually, neither in aperture priority of full manual mode, the aperture is locked tightly in place. If you select the maximum f-stop at the widest focal length and you zoom in, you will see the f-stop change.

Just try it; if you actually posses the camera you claim you have....

[achuang]

Say what you want about me being wrong Razr, but everyone else who has read what i posted knows it is correct. And prospero's post was a more detailed and very well written explanation of aperture size. What you're saying is that every person who has posted is wrong and that you're the only one who is right.
My last post in this thread. Here are 2 links, have a read and learn to admit when you're wrong.

http://photonotes.org/cgi-bin/entry.pl?id=Variableaperturezoomlens

http://photonotes.org/cgi-bin/entry.pl?id=Constantaperturezoomlens

[TheWengler]

For those of you who respond to Razr, does it really matter if he agrees with you or not? Every post that's not by Razr is against him. I'd call that a win. If you don't ignore the troll then he won't go back under the bridge. All that really matters here is that the TS doesn't leave misinformed.

[fionndruinne]

Actually, neither in aperture priority of full manual mode, the aperture is locked tightly in place. If you select the maximum f-stop at the widest focal length and you zoom in, you will see the f-stop change.

Just try it; if you actually posses the camera you claim you have....

That's what I was saying. Apparently Razr keeps his cameras locked in a dust-proof hermetically sealed location to avoid descending to our level of brute amateurishness by actually putting a grimy paw on the shutter.

[Rooz]

My last post in this thread. Here are 2 links, have a read and learn to admit when you're wrong.

http://photonotes.org/cgi-bin/entry.pl?id=Variableaperturezoomlens

http://photonotes.org/cgi-bin/entry.pl?id=Constantaperturezoomlens

and while we're in an educating mood...here's another one you may need to read.

http://www.thefreedictionary.com/maximum

[JTL]

Ed just won't give it up!

It's so f 'in funny...I'm beyond peeing my pants...now I'm gaging on the up-chuck!!!

Thank you guys! This is the best thread ever!!!!!!! :D:D:D

[DonSchap]

This is such a complete waste of time ... and will only serve to confuse a poor newbie who takes the time to read it. If it were up to me ... I scrap the thread and sincerely hope to God no one ever reads it, again.

The futuility displayed here is beyond redemption. :(

7 pages of complete and utter BUNK!

Oh yeah ... just how do I stop up to Aperture f/2.8 ... on a f/4-5.6 lens? In Manual or Av? I figure I can save a lot of money on high-priced glass if we can figure that one out. :p

[D Thompson]

Why do you guys keep repeating that asinine conclusion when in fact, I have never mentioned such? You’ve already segued off topic. The topic is not constant aperture zoom(s) but does aperture priority lock the aperture in place no matter what: at least that is my thesis.

Check page 1 post #8 where you wrote "The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range."

If Av (Aperture priority), the aperture (regardless of setting) is locked down tight and cannot move (open or close). Disprove my thesis by demonstrating how the aperture is not fixed in place in Av and M modes.

It's very easy to disprove and we have tried to tell you several times, but you refuse to listen. Here goes one more try. Now follow along at home with your camera with a variable f-stop lens attached and the zoom set to the widest angle.

Turn camera on, take the lens cap off, and set mode to AV or M. Set aperture to the fastest you can.

Zoom the lens to its longest setting and take a look at your aperture now. It changed. You may have to half press the shutter button.

Now here is how it goes on my Canon 20D with the Canon efs 10-22 f3.5-4.5 lens attached. I've got it set to 10mm and in AV mode I set the aperture to f3.5. I then zoom to 22mm and my aperture has changed to f4.5. In fact, when this lens is set to 22mm the aperture of f3.5 is not even available to be set in AV or M or any other mode.

Now, is your post {The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose,} total BS or not?

[DonSchap]

Now, is your post {The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose,} total BS or not?

Of course it is "BS" ... You can watch it happen dynamically.

1) Turn the camera on
2) Crank the zoom to minimum focal length ... for a 70-300mm, that would be 70mm
3) Set the Mode dial to Av (for the sake of argument)
4) turn your aperture ring or dial to MAX aperture (f/4)
5) Ok ... prepare thy self ... crank the zoom in to 300mm
6) Read the setting of the Aperture ... probably looks a hell of a lot like f/5.6 ... if not, its probably time for a new camera.

You don't have to touch anything other than the zoom ring ... when you set the Aperture to maximum allow width and crank the zoom out on one of these prosumer lenses ... it just changes ... Manual, AV, S, P, AUTO ... who cares ... it cannot stay the same physically, electronically or even with your internal metering. Light is reduced in these cheaper lenses when you zoom in and stretch that lens tube. How much? In this case, ONE FULL f/STOP! :eek:

If you zoom out and return the the lens to 70mm ... the APERTURE returns to f/4.

That's it in a nut shell.

[Rooz]

Of course it is "BS" ... You can watch it happen dynamically.

1) Turn the camera on
2) Crank the zoom to minimum focal length ... for a 70-300mm, that would be 70mm
3) Set the Mode dial to Av (for the sake of argument)
4) turn your aperture ring or dial to MAX aperture (f/4)
5) Ok ... prepare thy self ... crank the zoom in to 300mm
6) Read the setting of the Aperture ... probably looks a hell of a lot like f/5.6 ... if not, its probably time for a new camera.

You don't have to touch anything other than the zoom ring ... when you set the Aperture to maximum allow width and crank the zoom out on one of these prosumer lenses ... it just changes ... Manual, AV, S, P, AUTO ... who cares ... it cannot stay the same physically, electronically or even with your internal metering. Light is reduced in these cheaper lenses when you zoom in and stretch that lens tube. How much? In this case, ONE FULL f/STOP! :eek:

If you zoom out and return the the lens to 70mm ... the APERTURE returns to f/4.

That's it in a nut shell.

thanks for adding to the BUNK. it just wouldn;t be the same without you. :)

[tim11]

For those of you who respond to Razr, does it really matter if he agrees with you or not? Every post that's not by Razr is against him. I'd call that a win. If you don't ignore the troll then he won't go back under the bridge. All that really matters here is that the TS doesn't leave misinformed.

Who cares about winning or losing arguing with a stranger on the net. We just have to correct some lunatic thesis so it doesn't confuse some newbies who might be seeking facts in here.

[r3g]

You guys are going to blow the OPs mind with this crap.. Wont lie though it is the most entertaining thread Ive ever read on this forum :rolleyes:

[TheWengler]

Who cares about winning or losing arguing with a stranger on the net. We just have to correct some lunatic thesis so it doesn't confuse some newbies who might be seeking facts in here.

Uhm...how about the long list of people arguing with him? He was corrected on the first page of this thread. We're now on page 8.

[tim11]

TheWengler
He brought it upon himself by arguing and back up with some theory every single page of this thread; and that's how this thread grows to 8 pages.
However, I'm not going to start arguing with you now as RAZR keep saying it 'this thread is not about razr..." ;)

[Razr]

the lens has no bearing on the shutter speed so it's not relevant in the slightest to this discussion. The lenses (glass elements) have everything to do with the discussion. if the lens is just a tube with some glass in it what regulates the amount of light passing from the front of the lens to the rear element and ultimately the camera ? The aperture; of course. ie: where exactly are the aperture blades located ? or is that just an electronic figment of our imagination ? It would not make any difference where the aperture blades are located. The important matter is the aperture controls the amount (value of)of the light striking the sensor.

[zmikers]

This is such a complete waste of time ... and will only serve to confuse a poor newbie who takes the time to read it. If it were up to me ... I scrap the thread and sincerely hope to God no one ever reads it, again.

The futuility displayed here is beyond redemption. :(

7 pages of complete and utter BUNK!

Oh yeah ... just how do I stop up to Aperture f/2.8 ... on a f/4-5.6 lens? In Manual or Av? I figure I can save a lot of money on high-priced glass if we can figure that one out. :p

LMAO...What took you so long to get here Don?

[JTL]

LMAO...What took you so long to get here Don?He was too busy burning and cutting up pictures of the 40D! :D

The ultimate reality show. It's called One Camera, Two Men

Episode 1: Don and Razr are in a room facing each other across a table with a video camera rolling. Every week a new guest star appears opposite Razr. I'd never watch anything else! :D:D:D

[Razr]

If you are unable to change your aperture in Av mode then there's something wrong with your camera. It is you who are misinformed about what Av mode is and does-see below. Aperture priority mode is the mode that allows you to be able to change your aperture ?? You cannot set the aperture (on one f/stop in Av mode) and then say: " allows you to be able to change your aperture". That makes no sense. You cannot set a camera one one f/stop in Av mode, then "allow it to change". and the camera decides on the shutter speed. If you read your own definition, it is not correct: Av mode means the aperture is locked on a given f/stop while the shutter is used to balance the exposure, as per Wikipedia (or any other resource)
Aperture priority
From Wikipedia, the free encyclopedia

Aperture priority, often abbreviated Av or A on a camera dial, is a setting on some cameras that allows the user to choose an aperture while the camera selects a shutter speed to match. The camera will ensure proper exposure. This is different from manual mode, where the user must decide both values, shutter priority where the user picks a shutter speed with the camera selecting the aperture to match, or program mode where the camera selects both.

The main purpose of using aperture-priority mode is to control the depth of field. Aperture priority is useful in landscape photography, where a narrow aperture is necessary if objects in foreground, middle distance, and background are all to be rendered crisply, while shutter speed is often immaterial. It also finds use in portrait photography, where a wide aperture is desired to throw the background out of focus and make it less distracting.

Another common use of aperture priority mode is to suggest how the camera should decide a shutter speed, without risking a poor exposure. In landscape photography a user would select a small aperture when photographing a waterfall, hoping to allow the water to blur through the frame. When shooting a portrait in dim lighting, the photographer might choose to open the lens to its maximum aperture in hopes of getting enough light for a good exposure.

In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures. Commonly, lenses provide greatest resolving power with a relatively medium-sized aperture.[/
Do you and the others now get the fact that the aperture is frozen on one f/stop in Av mode? Get it? FYour camera seems to be the only one that can break what is called aperture priority.

It is not me who has been struggling with what happens when a person chooses Av mode: it is you and they. It's aperture priority because the photographer chooses the aperture suited for a particular photograph to give a suitable depth of field. BINGO! Which at the same time, tells you why Av mode holds-freezes-locks the aperture on one f/stop (my original thesis), regardless of why the photographer chose or chooses to use Av mode.
Got it?

[tim11]

CLAP CLAP CLAP.

Enough of your mumble jumble and back to shooting higher than max. aperture.

Have you done this little simple test?



1) Turn the camera on
2) Crank the zoom to minimum focal length ... for a 70-300mm, that would be 70mm
3) Set the Mode dial to Av (for the sake of argument)
4) turn your aperture ring or dial to MAX aperture (f/4)
5) Ok ... prepare thy self ... crank the zoom in to 300mm
6) Read the setting of the Aperture ... probably looks a hell of a lot like f/5.6 ... if not, its probably time for a new camera.

You don't have to touch anything other than the zoom ring ... when you set the Aperture to maximum allow width and crank the zoom out on one of these prosumer lenses ... it just changes ... Manual, AV, S, P, AUTO ... who cares ... it cannot stay the same physically, electronically or even with your internal metering. .....

[D Thompson]

CLAP CLAP CLAP.

Enough of your mumble jumble and back to shooting higher than max. aperture.

Have you done this little simple test?

Of course he hasn't, nor has he done mine either (same test) or he wouldn't be continuing in this BS. Matter of fact, I'm done with this thread as there is no sense in continuing.

[Razr]

I think this is the problem that Razr has understanding. He thinks that when it's in Av that the aperture is stuck in place and that we can't change it. That is your gross misunderstanding of what I have said.
I know the photographer can choose any aperture to use in Av mode. At f/whatever in Av mode, the camera is "boss", choosing the correct shutter speed to balance the exposure. And that the opposite happens in shutter priority mode where the shutter is "frozen" in place while the aperture "varies" as he calls it. Which is 100% correct in that the aperture does, in Shutter priority: vary (changes the aperture).
But you knew that. This varying of the aperture is not the same as a variable aperture lens. Your own gross mischaracterization (misunderstanding) of what I have posited.
Go to Wikipedia or read the definition above for what aperture priority is and does.

[Ray Schnoor]

If you read your own definition, it is not correct: Av mode means the aperture is locked on a given f/stop while the shutter is used to balance the exposure, as per Wikipedia (or any other resource)

---snip---

Got it?
Yes, I got it now. Let's look at Wikipedia (http://en.wikipedia.org/wiki/Lenses_for_SLR_and_DSLR_cameras)

The maximum aperture (http://en.wikipedia.org/wiki/Aperture) for a zoom lens may be same for all focal lengths, but it is more common that the maximum aperture is greater at the wide-angle end than at the telephoto end of the zoom range. For example, a 100 mm to 400 mm lens may have a maximum aperture of 4.0 at the 100 mm end but only 5.6 at the 400 mm end of the zoom range.
I certainly got that a zoom lens may have a different max aperture at the short and long ends.

Let's look at another resource, say the manufacturer of your 4/3rds cameras of choice(Olympus):
Olympus/Zuiko makes some variable max-aperture zoom lenses for their 4/3rds cameras. I especially like how they have DOF values on their website for their lenses.

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/11-22_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/14-54_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/50-200_28-35/index.asp

What I can't understand is why there is no DOF info on these lenses at the middle range or long end for say f/2.8 and no DOF info on these lenses at the long end for say f/3.2. Could it possibly be because Olympus/Zuiko does not know how to "lock" the aperture at f/2.8 in Av mode for the entire zoom range, or because zooming these lenses causes the max aperture to change from f/2.8 to f/3.5 as it says in their literature/website. Hmmmmmmmmm?

edit: I hope that this is not just a limitation of the 4/3rds format.:D

Ray.

[Prospero]

It is you who are misinformed about what Av mode is and does-see below. ?? You cannot set the aperture (on one f/stop in Av mode) and then say: " allows you to be able to change your aperture". That makes no sense. You cannot set a camera one one f/stop in Av mode, then "allow it to change". If you read your own definition, it is not correct: Av mode means the aperture is locked on a given f/stop while the shutter is used to balance the exposure, as per Wikipedia (or any other resource)
Do you and the others now get the fact that the aperture is frozen on one f/stop in Av mode? Get it?

It is not me who has been struggling with what happens when a person chooses Av mode: it is you and they. BINGO! Which at the same time, tells you why Av mode holds-freezes-locks the aperture on one f/stop (my original thesis), regardless of why the photographer chose or chooses to use Av mode.
Got it?

Razr, you obviously don't have a clue.
The Wikipedia article you link to does not support your case. It says that in apperture priority mode you select the apperture and the camera calculates the shutterspeed. That's all. There's really nothing in that article about locking appertures into place.

The only thing which is locked when using the aperture priority mode are the apperture blades if and only if you select the maximum aperture.
If you don't select the maximum apperture even the apperture blades change as you zoom in (they will go wider).
However, due to zooming in, the relative apperture gets smaller due to the increase in focal length. Thus there is less light that will reach the sensor which is why the f-stop gets larger.

I guess in the next thread you will start claiming that if you twist the zoom ring of a lens far enough, you can push a 70-300 up to 400mm.... And that with a constant apperture of f/4.... Simply amazing :D

[Razr]

All Razr needs to do is pop a variable max-aperture on a body and try it, as I suggested. I did that back in 1983 with my Pentax Super Program and Vivitar Series 1 (67mm) one-button Macro f/3.5 constant aperture lens. Man, if only a 17-70mm which was really f/2.8 across the full range cost as little as that Sigma does... Too bad you haven't tried or didn't know you could do just that: make your lens an f/2.8 (or whatever) constant aperture lens.
Try it: set your camera body on Av and f/2.8 then zoom.
Youll see the shutter speed (only) change as more or less light enters the lens.
Go ahead-give it a go.

[GaryS]

To have this make sense, you need to remember that the aperature number is a ratio between the size of the opening in the blades, and the mm length of the lens.

In a lens with constant aperture, the aperture blades widen as the lens zooms to keep that ratio the same. Its mechanically driven by the zoom twist. In a lens with a variable max aperture, the blades generally open too as the lens zooms, but not enough to completely compensate for the increase in length. So the max aperture number changes.

[Prospero]

I did that back in 1983 with my Pentax Super Program and Vivitar Series 1 (67mm) one-button Macro f/3.5 constant aperture lens. Too bad you haven't tried or didn't know you could do just that: make your lens an f/2.8 (or whatever) constant aperture lens.
Try it: set your camera body on Av and f/2.8 then zoom.
Youll see the shutter speed (only) change as more or less light enters the lens.
Go ahead-give it a go.

Actually, you will see that it reaches f/3.2 before you reach 20mm.
And believe me, I posses that lens and I tried it (the reason I did that was to see for what length it is actually f/2.8, not to test the obvious).

And please cut the crap about your experiences with cameras back in 1983. If you were really a professional photographer back then, you would have realized that everything you said in this thread is complete nonsense.

[Razr]

Ray: Yes, I got it now. Let's look at Wikipedia

Quote:
The maximum aperture for a zoom lens may be same for all focal lengths, "May be the same for all focal lenths" being the operative phrasing, the "may be" being when the lens is operated in Av. mode. but it is more common that the maximum aperture is greater at the wide-angle end than at the telephoto end of the zoom range. For example, a 100 mm to 400 mm lens may have a maximum aperture of 4.0 at the 100 mm end but only 5.6 at the 400 mm end of the zoom range. Which is absolutely true in Program mode, not so in Av. since the aperture can be set at f/4 in Av mode and at 400m, would still be f/4. I certainly got that a zoom lens may have a different max aperture at the short and long ends.

Let's look at another resource, say the manufacturer of your 4/3rds cameras of choice(Olympus):
Olympus/Zuiko makes some variable max-aperture zoom lenses for their 4/3rds cameras. I especially like how they have DOF values on their website for their lenses.

http://www.olympusamerica.com/cpg_se...8-35/index.asp

http://www.olympusamerica.com/cpg_se...8-35/index.asp

http://www.olympusamerica.com/cpg_se...8-35/index.asp

What I can't understand is why there is no DOF info on these lenses at the middle range or long end for say f/2.8 Because they didn't test (never test) the lenses using f/2.8 in Av mode? and no DOF info on these lenses at the long end for say f/3.2. ?? what does f/3.2 have to do with it? Could it possibly be because Olympus/Zuiko does not know how to "lock" the aperture at f/2.8 in Av mode for the entire zoom range, or because zooming these lenses causes the max aperture to change from f/2.8 to f/3.5 as it says in their literature/website. Hmmmmmmmmm?

Ray. As I noted before and even with OLYMPUS, all such "tests" are conducted in "P" mode, not Av. And the aperture (no matter which is chosen) is locked in Av.

[Prospero]

Because they didn't test (never test) the lenses using f/2.8 in Av mode?

Right, they make a lens that actually has a wider apperture than they claim and show in such online resources :confused:

Now that is some good marketing :rolleyes:

If the 17-70 f/2.8-4.5 could do f/2.8 at 70 they would call it a 17-70 f/2.8. No question about it :).

[Razr]

Say what you want about me being wrong Razr, but everyone else who has read what i posted knows it is correct. And prospero's post was a more detailed and very well written explanation of aperture size. What you're saying is that every person who has posted is wrong and that you're the only one who is right.
My last post in this thread. Here are 2 links, have a read and learn to admit when you're wrong.
Aperture priority
From Wikipedia, the free encyclopedia

Aperture priority, often abbreviated Av or A on a camera dial, is a setting on some cameras that allows the user to choose an aperture while the camera selects a shutter speed to match. The camera will ensure proper exposure. This is different from manual mode, where the user must decide both values, shutter priority where the user picks a shutter speed with the camera selecting the aperture to match, or program mode where the camera selects both.

The main purpose of using aperture-priority mode is to control the depth of field. Aperture priority is useful in landscape photography, where a narrow aperture is necessary if objects in foreground, middle distance, and background are all to be rendered crisply, while shutter speed is often immaterial. It also finds use in portrait photography, where a wide aperture is desired to throw the background out of focus and make it less distracting.

Another common use of aperture priority mode is to suggest how the camera should decide a shutter speed, without risking a poor exposure. In landscape photography a user would select a small aperture when photographing a waterfall, hoping to allow the water to blur through the frame. When shooting a portrait in dim lighting, the photographer might choose to open the lens to its maximum aperture in hopes of getting enough light for a good exposure.

In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures. . Commonly, lenses provide greatest resolving power with a relatively medium-sized aperture. "Ta-da"!
Of course you all may have missed the most important (for this discussion)part of the Wikipedia statement so I'll repeat:
"force the camera to operate the lens at its optimum apertures, the operative phrase which, in laymen's terms, means forcing the camera to use the aperture of choice and/or any other "optimum aperture": my original thesis;
thanks Wikipedia.

[Ray Schnoor]

"May be the same for all focal lenths" being the operative phrasing, the "may be" being when the lens is operated in Av. mode..
Wrong. "May be the same for all focal lengths" only refers to constant max-aperture lenses vs variable max-aperture lenses such as these 2 examples:
http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3325&navigator=6
http://www.sigmaphoto.com/lenses/lenses_all_details.asp?id=3320&navigator=6
Let's look at another resource, say the manufacturer of your 4/3rds cameras of choice(Olympus):
Olympus/Zuiko makes some variable max-aperture zoom lenses for their 4/3rds cameras. I especially like how they have DOF values on their website for their lenses.

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/11-22_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/14-54_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/50-200_28-35/index.asp

What I can't understand is why there is no DOF info on these lenses at the middle range or long end for say f/2.8 and no DOF info on these lenses at the long end for say f/3.2. Could it possibly be because Olympus/Zuiko does not know how to "lock" the aperture at f/2.8 in Av mode for the entire zoom range, or because zooming these lenses causes the max aperture to change from f/2.8 to f/3.5 as it says in their literature/website. Hmmmmmmmmm?
Because they didn't test (never test) the lenses using f/2.8 in Av mode? As I noted before and even with OLYMPUS, all such "tests" are conducted in "P" mode, not Av. And the aperture (no matter which is chosen) is locked in Av.
Wrong again. I don't think I have ever seen any camera in "P" mode choose the minimum aperture possible on a lens. I guess maybe if they are taking a direct shot of the sun, maybe. Do you suppose they just sit there fiddling with the light source until they get at those f/#s. No, they set the f/#s in aperture priority mode to save time. Duh....

edit: Actually, I doubt they even perform these tests. They probably just do the math on the depth of field with a certain focal length/aperture value and put down the values. This would be even more curious why they do not include the DOF values for f/2.8 at medium and long ends of the zoom range.

And I included the f/3.2 comment because that is the max aperture value at the medium range of the zoom, at least according to their website.

Another quote from their wetsite:"Maximum Aperture f 2.8 Wide - f 3.5 Telephoto"

Ray.

[Razr]

That's what I was saying. Apparently Razr keeps his cameras locked in a dust-proof hermetically sealed location to avoid descending to our level of brute amateurishness by actually putting a grimy paw on the shutter."Grimy paw"?

[Razr]

(SNIP)
Oh yeah ... just how do I stop up (STOP UP?) to Aperture f/2.8 ... on a f/4-5.6 lens? Why did you post such a nonsensical question? To amuse yourself or others? In Manual or Av? I figure I can save a lot of money on high-priced glass if we can figure that one out. More nonsense.

[Prospero]

Razr, that's not at all what they mean by "forcing a camera to use the optimum apertures".

The optimum aperture is the aperture where the lens performs best. This is generally between f/5.6 and f/11. It is a couple of stops away from the maximum aperture at a certain focal length.
Yes, with aperture priority, you can force a camera to use that aperture. It is easily within the range of apperture values available.
However, you can still not force the camera to use an apperture that is not available...

[JTL]

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.Amusing as this thread is, it all goes back to the above statement. It is simply not true. Nothing can make it true. All the word games and symantic gymnastics in the world created to defend the statement are meanilngess. I suggest that all efforts be redirected at this statement and this statement alone and that any other statements made in defense of it be ignored as they are just distractions.

If it weren't the funniest (yet most pathetic) thing in all of mediadom...I don't think this thread would have lasted this long.

[Razr]

(SNIP) Razr, you obviously don't have a clue.
The Wikipedia article you link to does not support your case. It says that in apperture priority mode you select the apperture and the camera calculates the shutterspeed. That's all. There's really nothing in that article about locking appertures into place. The mote in your eye let you miss this part of the Wikipedia article which says: "In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures. How did you miss that in the Wikipedia article? Of course "force the camera" to operate the lens at its optimum aperture" simply means any aperture of the photographer's choce (of all the apertures on any given lens).
How did you miss that crucial (and 100% germane) sentance? The only thing which is locked when using the aperture priority mode are the apperture blades Oh thank you-thank you. I finally get someone to see the light so to speak. ...if and only if you select the maximum aperture. not true. Av mode can be set on any available aperture. (SNIP) I guess in the next thread you will start claiming that if you twist the zoom ring of a lens far enough, you can push a 70-300 up to 400mmOnly a total photgraphic neophyte could even think of duch an absurd posit.

[Razr]

Amusing as this thread is, it all goes back to the above statement. It is simply not true. Nothing can make it true. This Wikipedia article (below) makes it "true": From Wikipedia:
"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures. "Optimum apertures" being the ultimate choice of the photographer. All the word games and symantic gymnastics in the world created to defend the statement are meanilngess. I'm sure you'll write Wikipedia about their "symantic gymnastics". If it weren't the funniest (yet pathetic) thing in all of mediadom...I don't think this thread would have lasted this long. From Wikipedia:
"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures.

Don't foget to tell them what they (don't) know about aperture priority, them daring to publish such nonsense!

[JTL]

The mote in your eye let you miss this part of the Wikipedia article which says: How did you miss that in the Wikipedia article? Of course "force the camera" to operate the lens at its optimum aperture" simply means any aperture of the photographer's choce (of all the apertures on any given lens).
How did you miss that crucial (and 100% germane) sentance? Oh thank you-thank you. I finally get someone to see the light so to speak. not true. Av mode can be set on any available aperture. Only a total photgraphic neophyte could even think of duch an absurd posit.Now Wikipedia trumps physical reality!

Because the writer of the Wikipedia statement was sloppy (or ignorant or stupid) and left out the part that says: "force the camera, within the limits of max aperture for a given focal length" we have to listen to these endless WRONG rants...AMAZING BUT TRUE! :D:D:D

Too bad the World Weekly News is out of business. We could have gotten some quotes from them as well. There's always the Enquirer, I guess...:D:D:D

[Prospero]

The mote in your eye let you miss this part of the Wikipedia article which says: How did you miss that in the Wikipedia article? Of course "force the camera" to operate the lens at its optimum aperture" simply means any aperture of the photographer's choce (of all the apertures on any given lens).
How did you miss that crucial (and 100% germane) sentance?


No, if you actually read the wikipedia article one sentence further you will read:

Commonly, lenses provide greatest resolving power (http://en.wikipedia.org/wiki/Resolving_power) with a relatively medium-sized aperture.

Hence, the medium sized aperture - which would be somewhere between f/5.6-f/11 - is the optimum aperture which is refered to in the sentence before.

not true. Av mode can be set on any available aperture.

Yes, if you quote out of context, you can make everything seem untrue. What I said was that only at the maximum apperture and minimum for that matter, the apperture blades will stay in the same position if you zoom in. For the other focal lengths, the blades will change when zooming to make sure the f-stop stays constant.

Only a total photgraphic neophyte could even think of duch an absurd posit.

Of course that is a absurd posit. But it is just as absurd as opening up the diaphragm of a lens more than its maximum.
So who is the neophyte here... :)

[Ray Schnoor]

Now we are getting somewhere
So... You mean like for the 17-70 sigma... its F/2.8-4.5 which means at 17ish its maxed at 2.8 and 70 its maxed at 4.5? so it cant go below 4.5 at 70 but like the 70-200 F/4 COULD go to f/4 at 70 AND 200? so its just the max? and its not fixed and can be shrunk? thanks BTW those were fast replies!
Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.
not true. Av mode can be set on any available aperture.
Since f/2.8 is not available at the long end of said Sigma 17-70 f/2.8-4.5 lens, you obviously cannot set it at f/2.8 in Av mode at the long end of the zoom range.

Finally, a statement from Razr I can agree with. Thank you.:)

Ray.

[Razr]

Razr, that's not at all what they mean by "forcing a camera to use the optimum apertures".
The optimum aperture is the aperture where the lens performs best. I got no problem with that, except they said "optimum apertures", (plural). This is generally between f/5.6 and f/11. Generally quoted as being "the sweet spot" or "two stops down from the maximum aperture". (SNIP) Yes, with aperture priority, you can force a camera to use that aperture.My precise point all along.
However, you can still not force the camera to use an apperture that is not available... I never said so nor have I ever suggested you could (use an unavailable aperture-duh.)

[Ray Schnoor]

This (http://en.wikipedia.org/wiki/Aperture_priority)Wikipedia article makes it "true

"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures within the limits of maximum/minimum aperture for a given focal length of the lens."

OK! There we go.

Ray.

[DonSchap]

You know, there this bridge in Brooklyn, they've been trying to sell since forever ... and lakeshore property on this volcanic island ...

Look, Razr, you're a sharp guy ... don't you have a way to test the explanations out?

Keep a record of your settings ... and try to get back to us with a list out. I'm really interested in seeing some tangible results to back up this array of rather dubious and inaccurate discussion that are leading to the bleeding edge of "non-discovery", because I know I sure as hell can't get the lenses to do what you say with what I have, here ... and I do have a lens or two. :cool:

Thanks

[Prospero]

1. I got no problem with that, except they said "optimum apertures", (plural).

2. Generally quoted as being "the sweet spot" or "two stops down from the maximum aperture".

3. My precise point all along.

4. I never said so nor have I ever suggested you could (use an unavailable aperture-duh.)

1. They use the plural because different lenses have different optima and the optimum may vary with focal length. A 17mm f/8 may be best while at 70mm f/5.6.

2. Yes, I know they call it the sweet spot too. But optimum aperture is a more easily understandable term for readers with little knowledge of photography. Two stops down from the maximum is not even accurate. Sometimes one stop down will reach the optimum, sometimes 3 stops is needed.

3. No, that is not your precise point all along. You forget that the word 'that' in my sentence refers to a medium apperture and not the maximum apperture.

4. You suggested it, you implied it, and you even said it explicitly. You said a 17-70 f/2.8-4.5 can shoot at f/2.8 at 70mm. It simply cannot. Thus, f/2.8 is an unavailable apperture at 70mm which cannot be used.

[Ray Schnoor]

Let's look at another resource, say the manufacturer of your 4/3rds cameras of choice(Olympus):
Olympus/Zuiko makes some variable max-aperture zoom lenses for their 4/3rds cameras. I especially like how they have DOF values on their website for their lenses.

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/11-22_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/14-54_28-35/index.asp

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/50-200_28-35/index.asp

What I can't understand is why there is no DOF info on these lenses at the middle range or long end for say f/2.8 and no DOF info on these lenses at the long end for say f/3.2. Could it possibly be because Olympus/Zuiko does not know how to "lock" the aperture at f/2.8 in Av mode for the entire zoom range, or because zooming these lenses causes the max aperture to change from f/2.8 to f/3.5 as it says in their literature/website. Hmmmmmmmmm?

edit: I hope that this is not just a limitation of the 4/3rds format.:D

Ray.
Because they didn't test (never test) the lenses using f/2.8 in Av mode? ?? what does f/3.2 have to do with it? As I noted before and even with OLYMPUS, all such "tests" are conducted in "P" mode, not Av. And the aperture (no matter which is chosen) is locked in Av.
It's just must be coincidental how Olympus provides DOF data at f/2.8 for this lens at the long end of the zoom range

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/90-250_28/index.asp

but fails to do the same for this lens at the long end of the zoom range

http://www.olympusamerica.com/cpg_section/lens/dea/products/lens/50-200_28-35/index.asp

if your assertion is true that when you set the aperture value at f/2.8 at the short end of the zoom it stays a constant f/2.8 as long as you are in Av or M mode.
Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

I wonder why they didn't make an attempt to supply that DOF info?????

Ray.

[JTL]

"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures within the limits of maximum/minimum aperture for a given focal length of the lens."

OK! There we go.

Ray.Ray, please do us all a GIGANTIC favor and post that correction to Wikipedia so that Razr can't use Wikipedia to support his ridiculous word games. Thanks. :)

--------------------------------------
Razr:

By the way, the below statement is STILL wrong...and I have seen nothing posted by you to acknowledge that its wrong. Nothing that you can write or quote can make it right:

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

How about this?:

I never said so nor have I ever suggested you could (use an unavailable aperture-duh.)Oh yes you did my friend...read it again...and again...and again...you're never getting away from this one...
Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

Your Kafka-esque/Orwellian approach would be better suited if this were some kind communist totalitarian environment and you were the information minister (scary, eh?). They need people like you in North Korea...

Also...what kind of "pro" gets their information from Wikipedia and uses it to defend a statement that is wrong? You're a pro alright...although at something that has very little to do with photography (unless you count photographing bulls defecating).

----------------------------
Update:

Hey, it's a couple of hours later and I just checked aaaaaaannnnnd...yep...ITS STILL WRONG!!!!! :D:D:D

I'll check again later in a couple of hours to see whether the laws of physics have changed, or a parallel universe exists or if there's been some major technological breakthrough...a lot can happen in two hours.

[Rooz]

lol i can't believe this. i really can't.

[AdamW]

Reading this thread has been like watching a train wreck in slow motion. It's tragic and terrible and senseless--and I can't look away. :eek: :p :confused:

[tim11]

LOL :D:D
It's me against the world and the world is wrong. :D:D:D Naturally.

[zmikers]

I never said so nor have I ever suggested you could (use an unavailable aperture-duh.)

Sorry M8, but that's what you've ben saying all along. You have siad that a lens that has a max aperture of f/2.8-3.5 can use f/2.8 along the whole zoom range and that is using an unavailable aperture because at the long end of the zoom f/2.8 is "unavailable as its max aperture is f/3.5.

Can you please explain to all of us what a max aperture of f/2.8-3.5 really means if it doesn't mean that the max aperture is variable and changes as the lens zooms. Why would manufacturers lable their lenses this way if it is not true? Don't you think if the lens could be set to f/2.8 across the entire zoom range, the manufacturer would advertise this as to sell more of the product. Come on M8, get your head out of the clouds and stop this none sense.

[Razr]

You know, there this bridge in Brooklyn, they've been trying to sell since forever ... and lakeshore property on this volcanic island ...

Look, Razr, you're a sharp guy ... don't you have a way to test the explanations out?

Keep a record of your settings ... and try to get back to us with a list out. I'm really interested in seeing some tangible results to back up this array of rather dubious and inaccurate discussion that are leading to the bleeding edge of "non-discovery", because I know I sure as hell can't get the lenses to do what you say with what I have, here ... and I do have a lens or two. :cool:

ThanksNo test needed: and here's why:
From Wikipedia:
"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures. Any person with the slightest bit of knowledge about the brute mechanical end of photogrpahy knew/knows what Wikipeida says (above) is 100% true.
The operative phrase being: "allows the photographer to force the camera to operate the lens at its optimum aperure":
which means from wide open or anywhere in-between.

If you have any differences about what I said about aperture priority, take it up with Wikipedia, which literally pimp slapped all your uninformed arguments.

[tim11]

RAZR,
Can a photographer use F2.8 at 70 mm on a Sigma 17-70 F/2.8-4.5?

[JTL]

Razr:

I'm calling you out.

You're still not responding DIRECTLY to this quote of yours:

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

You like to avoid it, don't you?

You have yet to directly respond to the fact that it is WRONG! Do you deny that it's wrong? I don't give a hoot what Wikipedia says. I am talking about what YOU wrote.

Let's have it, Mr. "Pro".

[AdamW]

Ken Rockwell could do it.

[Razr]

Sorry M8, but that's what you've ben saying all along. You have siad that a lens that has a max aperture of f/2.8-3.5 can use f/2.8 along the whole zoom range and that is using an unavailable aperture because at the long end of the zoom f/2.8 is "unavailable as its max aperture is f/3.5. Please, show me (in/on an unassailable website), that precise statement about ("unavailable aperture"):
Google, Ask-you know, any URL I can search and read for myself. Can you please explain to all of us what a max aperture of f/2.8-3.5 really means if it doesn't mean that the max aperture is variable and changes as the lens zooms. Why would manufacturers lable their lenses this way if it is not true? Gladly. but first, you do know your question is mainly gobbledygook, incoherent? As for the "maximum aperture" you and others have fastened onto:
Maximum Aperture:
Max. Aperture F2.8
This simply states that the maximum aperture for the lens is F2.8.
http://www.megacameras.com/articles/What-Is----Aperture--53.html The above quote says all there is to say about "maximum aperture", which can be f/1:1.2 for my 55mm asph. CANON FD lens down to f/32 to f/45 at the smallest openings for small format to large format*.
+"F" numbers actually go up into the hundreds, not just f/45
*Each lens always-ALWAYS has only 1 (one) "maximum aperture" and it is ALWAYS stated somewhere on the barrel of the lens: that is, there is only one “maximum” aperture per lens.
I'm amused how each of you, in turn, fasten onto the others misunderstandings about the brute calculus in photography. I'd venture 98% of you have no idea about things photographic. Especially since you all seemed to have followed along like sheep with your misconception about what part of the camera does what when you use any thing but "P" mode.
__________________________________
The operative phrase in the Wikipedia quote is this:
allows the photographer to force the camera..., "Force (look it up) the camera to use an optimum aperture, "force" clearly stating the photographer can choose and shoot with any aperture within the limitations of the lens. Don't you think if the lens could be set to f/2.8 across the entire zoom range, the manufacturer would advertise this as to sell more of the product.
Let's look at this little blurb: Coolpix 995's Way of Achieving "Constant" Aperture
To partially overcome the problems caused by the variable aperture feature, Coolpix 995 can maintain aperture within 1/3 stop in effect before zoom operation started, if possible.
More precisely, the camera will do its best to keep the selected aperture with 1/3 stop as you zoom.
However, if the camera can maintain this 1/3 stop error range, aperture changes.
Consequently, constant aperture while zooming may or may not be maintained.
Note that this fixed aperture is only available in the Aperture-Priority mode and Manual Exposure mode when you can set aperture manually. You might want to point out that a dinky COOLPIX 995 P&S may not always be able to hold a set, constant aperture, though you and the rest should get the drift of my thesis by reading the COOLPIX blurb again, this time for its content.
Better for my thesis, just because a P&P cannot, may not hold a constant aperture, I assure you any SLR (shooting with automatic lenses in Av mode)most assuredly can (and easily does).

[Razr]

(SNIP) Of course that is a absurd posit. But it is just as absurd as opening up the diaphragm of a lens more than its maximum.
So who is the neophyte here... :)You. All you have to do to prove I ever said such is post the exact quote, which you cannot in that I never ever said or inferred any such silliness.

[Razr]

"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures within the limits of maximum/minimum aperture for a given focal length of the lens."

OK! There we go.

Ray. "Optimum": could also be the wide open position for portraiture, as with my EOS 70-200 f/2.8 "L". Or, closed down two stops from the maximum aperture.

"within the limits" merely means the focal length; no mystery there...unless

[SpecialK]

To have this make sense, you need to remember that the aperature number is a ratio between the size of the opening in the blades, and the mm length of the lens.

In a lens with constant aperture, the aperture blades widen as the lens zooms to keep that ratio the same. Its mechanically driven by the zoom twist. In a lens with a variable max aperture, the blades generally open too as the lens zooms, but not enough to completely compensate for the increase in length. So the max aperture number changes.


Dusty, that's the problem --> Razr doesn't know the difference between aperture and f-stop.

"Do you and the others now get the fact that the aperture is frozen on one f/stop in Av mode? Get it?"

See?

[D Thompson]

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.


Razr - you keep denying and denying and say show me proof. As you've chosen to ignore it I'm putting it up here once more. This thread, page #1, post #8.

Tell me that we're all reading it wrong and you're not saying that on a f2.8-4.5 that you can select f2.8 in AV or M mode and it is available throughout regardless of focal length.

How many more times do you have to be shown?

[Razr]

(SNIP)Can you please explain to all of us what a max aperture of f/2.8-3.5 really means if it doesn't mean that the max aperture is variable and changes as the lens zooms. I'll repeat here: only in "P" and "S" moded does the aperture setting change according to the focal setting.
IN "M" and "Av" modes, the aperture does not change until/unless the photographer sets (selects) another aperture-got it?
"Av" and "S" modes immobilze (lock-freeze) the aperture.

[tim11]

Instead of answering direct question Razr accuses people of misunderstanding, misquoting and wrongly 'inferred' what he has been saying.
The question we ask you now is straight and simple razr... should I repeat it?


Edit: I posted just before reading your last.
Are you saying that on a f2.8-4.5 that you can select f2.8 in AV or M mode and and F2.8 is available throughout the zoom range?

[cwphoto]

Oh dear.

First of all: Razr - you're a complete idiot.

That feels better, now the debate:

It's easier to understand if we are concise.

In a 'variable aperture' zoom lens (such as a 75-300/4-5.6) then the aperture itself may not change - by this I mean the actual aperture's diameter, not the aperture value.

However what does change is the maximum aperture value, which is a function of both the diaphragm's diameter and the focal length of the lens.

So while the actual diaphragm's diameter may not change when zooming, the aperture value most certainly will in the above example.

This is junior maths Razr. I assume you are older than a junior so therefore you are an idiot.

[cwphoto]

I'll repeat here: only in "P" and "S" moded does the aperture setting change according to the focal setting.
IN "M" and "Av" modes, the aperture does not change until/unless the photographer sets (selects) another aperture-got it?
"Av" and "S" modes immobilze (lock-freeze) the aperture.

The diaphragm's diameter may not change, but the aperture value changes proportionally to the focal length - regardless of exposure mode.

All that happens in M or Av mode is that the diaphragm's diameter may remain constant (or close to it for simplicity), the aperture value meanwhile must change as defined by mathematics.

Oh, did I mention you are an idiot?

[Nickcanada]

Okay I'm going to have to back up Razr on this. I tried that test with the aperture thing and the lens thing. I put the 35mm 1.4 on my camera and turned the ring on the lens and the aperture stayed at 1.4 no matter how much I turned the ring!!!!! all that happened was the image got fuzzy, but I think that's because my lens is crap.:confused: I'm thinking of getting something sharper. Any suggestions Razr? Oh and I think my zoom is broke too. The only way I can get bigger images is by walking closer? :confused: Have you ever had that problem? What a waste of money that lens was!:mad:

[AdamW]

Maybe Razr is Ken Rockwell. I've never seen them both in the same room.
:confused::eek:

[Razr]

Razr - you keep denying and denying and say show me proof. As you've chosen to ignore it I'm putting it up here once more. This thread, page #1, post #8.

Tell me that we're all reading it wrong and you're not saying that on a f2.8-4.5 that you can select f2.8 in AV or M mode and it "It" what? F/2.8 in Av mode? In Av mode, only the selected aperture (in this demonstration-f/2.8) setting is “available” to use and that throughout the zoom range. How many more times do you have to be shown? You're all reading it wrong.
I cannot believe people out there use Av mode and do not know what the aperture is doing (and not doing as in "not changing") in Av mode.

[griptape]

No test needed: and here's why:
Any person with the slightest bit of knowledge about the brute mechanical end of photogrpahy knew/knows what Wikipeida says (above) is 100% true.
The operative phrase being: "allows the photographer to force the camera to operate the lens at its optimum aperure":
which means from wide open or anywhere in-between.

If you have any differences about what I said about aperture priority, take it up with Wikipedia, which literally pimp slapped all your uninformed arguments.

Yeah... Because wikipedia isn't just some site that gathers knowledge from its users without any credentials... Oh wait... That's exactly what wikipedia is.

And aside from that:

"allows the photographer to force the camera to operate the lens at its optimum aperure":
which means from wide open or anywhere in-between.

I seriously suggest you learn to read. "Optimum aperture" (or aperure as you quoted it) does not mean wide open at the arbitrary number of your choosing, it means wide open at the mathematical ability of the lens at the given focal length. Optimum and imaginary aren't the same word. Sorry.

There are two possibilities here. 1. You're mentally retarded and you need a great deal of help because of your learning disability, or 2. You have never owned an SLR or SLR lens. Either way, I feel sorry for you.


Finally, why would every lens manufacturer list their lenses as "f/3.5-5.6" or "f/2.8-4" if they could be used at f/3.5 or f/2.8 throughout the entire focal length? What possible reason could there be aside from the fact that you're wrong for them to inform people that at the telephoto length, they'll only be getting f/5.6? Why wouldn't they just list their lens at the maximum aperture that you have found a magical way to invoke despite the fact that physics deem it impossible?

[Razr]

RAZR,
Can a photographer use F2.8 at 70 mm on a Sigma 17-70 F/2.8-4.5?In Av mode and full manal mode he can: In Av mode, the photographer selects f/2.8 and the camera body is forced to use the selected aperture.
In full manual mode, the photographer selects f/2.8 as their shooting aperture, adjusting the shutter speed and ISO (if neccessary) to balance the exposure.
_________________
Question for you: in full manual, the photographer (above) selects f/2.8 @ 1/320th sec. to start a shoot.
When he zooms, he is two stops over on his match needle reading.
Since the photographer will not change the aperture setting, what does the photographer have to do to balance the exposure?

[tim11]

"It" what? F/2.8 in Av mode? In Av mode, only the selected aperture (in this demonstration-f/2.8) setting is “available” to use and that throughout the zoom range. You're all reading it wrong.
I cannot believe people out there use Av mode and do not know what the aperture is doing (and not doing as in "not changing") in Av mode.

NO. YOU ARE WRONG. At full zoom of the lens in question (ie. sigma 17-70 f/2.8-4.5) only F/4.5 is available.

You are a bigger idiot than I previously thought you were since you keep denying you are wrong.

[D Thompson]

"It" what? F/2.8 in Av mode? In Av mode, only the selected aperture (in this demonstration-f/2.8) setting is “available” to use and that throughout the zoom range.

OK, real easy, just a yes or no answer will do. On a f2.8-4.5 (using your example on this thread, page#1, post#8) I can use the aperture of f2.8 at any focal length the lens has? Mode is set to AV or M of course.

You're all reading it wrong.
I cannot believe people out there use Av mode and do not know what the aperture is doing (and not doing as in "not changing") in Av mode.

I think all of us here but you have an ideal how to use AV and what it does.

[griptape]

In Av mode and full manal mode he can: In Av mode, the photographer selects f/2.8 and the camera body is forced to use the selected aperture.
In full manual mode, the photographer selects f/2.8 as their shooting aperture, adjusting the shutter speed and ISO (if neccessary) to balance the exposure.
_________________
Question for you: in full manual, the photographer (above) selects f/2.8 @ 1/320th sec. to start a shoot.
When he zooms, he is two stops over on his match needle reading.
Since the photographer will not change the aperture setting, what does the photographer have to do to balance the exposure?

Alright, that's it. This guy has never owned a DSLR. Leave him to his delusions. Any moron that has ever put their DSLR in manual mode (hell, it's the only mode I shoot in) knows that lenses state their aperture range for a reason, and that Razr is delusional. Let's just let this poor fellow fade away into his delusions of owning an actual SLR camera.

[TenD]

First of all Razr needs to be educated not ridiculed and maybe we all need a lesson in Semantics. Of course he did come on like we all needed to be educated. He's arguing aperture (opening), and maybe that doesn't change (but I think it does) but rather appears to change. I really don't know the inner workings of a lens. I do know however a variable aperture lens cannot attain a lens opening larger than the f-stop ratio advertised for a given focal length. It's a simple ratio and it's physically impossible to change it.


I will explain as best I can the way I understand aperture, focal length, and f-stop.

First, my out of context quote from Wikipedia's article on aperture:

"Zoom lenses typically have a maximum aperture (minimum f-number) of f/2.8 to f/6.3 through their range. A very fast zoom lens will be constant f/2.8 or f/2, which means the relative aperture will stay the same throughout the zoom range. A more typical consumer zoom will have a variable relative aperture, since it is harder and more expensive to keep the effective aperture proportional to focal length at long focal lengths; f/3.5 to f/5.6 is an example of a common variable aperture range in a consumer zoom lens."

The key words are relative aperture. An f-stop is very simply a ratio of the diameter of the aperture of a lens to the focal length. The tube a lens is built in is only so big, and this determines the maximum opening (aperture) the lens has. As focal length (the center of the lens to focal plane) increases the opening (aperture) required to transmit a given amount of light to the focal plane must increase. This ratio is constant, your aperture has to be a certain size for a given focal length to maintain a given f-stop.

Think of being in a railroad tunnel standing 10 feet from the exit(short focal length) looking out. You can see a huge opening (aperture) with lots of light coming in, there is plenty of light hitting you, enough to read a newspaper. Now back up into the tunnel a hundred feet(zoom in)the exit will appear like a much smaller opening (relative aperture) with much less light entering. Has the size of the aperture changed? No of course not, but your position to the opening has given it the appearance of being smaller...and, there is much less light reaching you now, and you"ll probably have some trouble reading the news now. The aperture is the same size but your position relative to the aperture has made it appear much smaller, with much less light reaching you.

Let's make a hypothetical lens, a 50-200 f/2-f/8. A lens is built in a tube much like the aforementioned railroad tunnel: lets say this tube is 25mm in diameter, that's as big as the opening can get, it physically can't get any bigger. I need all of this opening of 25mm to get an f stop of 2 at 50mm.

Now, I'll zoom my lens in to 200mm, my focal length has increased therefore my distance from the center of the lens to the focal plane has increased, just like moving back into the tunnel. I need more opening now to maintain f/2 but my lens is only 25mm in diameter: it can't physically get any larger. I can't make the opening any larger, and the opening now appears smaller because of the increased focal length. So my ratio has changed, I still have a 25mm tube but my ratio has changed 200mm divided by 25mm (the size of my tube) equals f/8. That's the best f-stop I can get with my hypothetical lens, the size of the opening (aperture) didn't change, but my ratio to focal length sure did.

[tim11]

In Av mode and full manal mode he can: In Av mode, the photographer selects f/2.8 and the camera body is forced to use the selected aperture.
In full manual mode, the photographer selects f/2.8 as their shooting aperture, adjusting the shutter speed and ISO (if neccessary) to balance the exposure.
----

You are WRONG. The photographer cannot force F/2.8 at full zoom on a Sigma 17-70 F/2.8-4.5. That's regardless of Av, M or whatever.

[Razr]

(SNIP)Are you saying that on a f2.8-4.5 that you can select f2.8 in AV or M mode and and F2.8 is available throughout the zoom range? Yes, in Av mode.

[griptape]

He has never used an SLR, or SLR lens. That's all there is to it. That or he's a troll. Let this discussion of 30 against 1 (very undereducated person) die. Razr is wrong, everyone else has more than chicken noodle soup for a brain. End of story.

[tim11]

OK, real easy, just a yes or no answer will do. On a f2.8-4.5 (using your example on this thread, page#1, post#8) I can use the aperture of f2.8 at any focal length the lens has? Mode is set to AV or M of course.



You can. :D

In Av mode and full manal mode he can: In Av mode, the photographer selects f/2.8 and the camera body is forced to use the selected aperture.
In full manual mode, the photographer selects f/2.8 as their shooting aperture, adjusting the shutter speed and ISO (if neccessary) to balance the exposure.


Finally, we get a straight answer - albeit the wrong one. RAZR... You may considered yourself a pro and google and wikepidia all you like the fact is you can't use F/2.8 at 70 mm (on a 17-70 F/2.8-4.5). Regardless of Av or M modes you try to use. It's the physical limitation of the lens. And at 70 mm, F4.5 becomes the optimum aperture. Accept it mate.

[DonSchap]

I'll repeat here: only in "P" and "S" moded does the aperture setting change according to the focal setting.
IN "M" and "Av" modes, the aperture does not change until/unless the photographer sets (selects) another aperture-got it?
"Av" and "S" modes immobilze (lock-freeze) the aperture.


This statement is just NOT true. I'm sorry, I've done it on my several cameras ... without firing a single shot ... and in the Av mode ... on a zoom lens:

1) focal length to minimum ...
2) set a variable aperture lens to MAXIMUM aperture
3) telephoto to the other side of the focal range

RESULT: the aperture will creep right up and close right down.

EVERY SINGLE CAMERA BODY, my friend. They all do it ... and I've got proof!

I'd make a movie of it ... but you can just get in your car, drive down to BEST BUY and do yourself ... live-action style. Living proof. There is no "locking" ... yes, if I return to the original focal length I started at, the aperture should and does return back to the original MAXIMUM. It does not stay at the higher aperture it got to.

By the way: "OPTIMUM Aperture" does not mean "MAXIMUM Aperture", "Optimum" is the photgrapher's choice for a particular type of shot. Be it in need of bokeh or light deficiency ... the photographer chooses the aperture from the available settings at that focal length. He/She chooses the "optimum" aperture and then the camera chooses the shutter-speed to support it. That is it.

My goodness ... this is a hard case. :o

You simply cannot get f/4 pounds of crap into a f/2.8 bag.

Look, I placed a chart at the very beginning of this thread to demonstrate EXACTLY what happens with two different lenses ... the 18-70mm and the 18-200mm. Please stop ignoring the rather simple and duplicatable facts and just accept this as common knowledge. Thank you ... and the horse you rode in on.

[TheWengler]

Troll - One who posts a deliberately provocative message to a newsgroup or message board with the intention of causing maximum disruption and argument.

[tim11]

All this time, at the back of of my mind I'd like to believe he is in fact a troll for the reason I hate to believe anyone can be that stupid.

[griptape]

For those of you wondering, Razr has NOT been an SLR owner, and is in line to order an Olympus E-3 that hasn't been released yet.

http://www.dcresource.com/forums/showthread.php?t=34858

After being an expert on the panasonic lens debate:http://www.dcresource.com/forums/showthread.php?p=258098#post258098

I suggest everyone add him to your mute list, as he's a moron who is just looking for attention.

[tim11]

For those of you wondering, Razr has NOT been an SLR owner, and is in line to order an Olympus E-3 that hasn't been released yet.

http://www.dcresource.com/forums/showthread.php?t=34858

I understood the concept even before I got my D80. It's nothing to do with owning a DSLR.
If I remember right RAZR also owns an FZ20 which has aperture of F2.8 throughout the range. I wonder if that :confused: him.

[TenD]

Yes, in Av mode.

Ok I though you were maybe being a clever troll and arguing opening(aperture), but that statement is simply, utterly WRONG. If the maximum aperture of a lens gives you f/4.5 at 70mm, the maximum f stop it can give you is f/4.5, it's physically impossible to get any more light to the sensor. The lens diameter is simply not big enough to allow an opening any larger.

[Razr]

Oh dear.

First of all: Razr - you're a complete idiot. And I'm turning you in for abuse of forum protocol. (SNIP) In a 'variable aperture' zoom lens (such as a 75-300/4-5.6) then the aperture itself may not change - by this I mean the actual aperture's diameter, not the aperture value. That makes no sense. However what does change is the maximum aperture value, which is a function of both the diaphragm's diameter and the focal length of the lens. Still nothing coherent. So while the actual diaphragm's diameter may not change when zooming, the aperture value most certainly will in the above example. Please Google "aperture priority".
Never mind. Here's one about "A": Coolpix 995's Way of Achieving "Constant" Aperture.
To partially overcome the problems caused by the variable aperture feature, Coolpix 995 can maintain aperture within 1/3 stop in effect before zoom operation started, if possible. More precisely, the camera will do its best to keep the selected aperture with 1/3 stop as you zoom.
However, if the camera can maintain this 1/3 stop error range, aperture changes. Consequently, constant aperture while zooming may or may not be maintained. Note that this fixed aperture is only available in the Aperture-Priority mode and Manual Exposure mode when you can set aperture manually. A CANON EOS fellow explains it better than me: a constant f/# zoom does *not* stop down at shorter focal lengths. look through any lens as you zoom for proof. the iris doesn't move.

the f/# of a complex lens system is the ratio between the size of the entrance pupil (what you see when you look through the front of the lens) and the focal length. this means that the magnification of the lenses in front of the actual iris dictate just how "fast" the lens is (i.e., they dictate how big the opening looks).

constant f/# zooms do not change the iris as they zoom. instead, this magnification is what changes. in fact, this goes for all zoom lenses really, but for constant f/# zooms, the magnification changes fast enough to keep pace with focal length, keeping the ratio between them constant.


This is junior maths(SIC) Razr. I assume you are older than a junior so therefore you are an idiot.As I noted before, your post here will be forwarded to the administrators.

[nqjudo]

OK, I'm really late into this thread but I had to come see what all these posts were about. I've always tried to be as polite as possible and avoid these controversies but enough is enough.

Razr, you are attacking everyone else's points but are either incapable or unwilling to define exactly where you stand. Your posts, more and more, are taking on the life of some sort of virtual chameleon; very bizarre looking but somehow able to blend in with the background.

One of two things is going on. Either you are completely glib or you are completely inept when it comes to expressing yourself. Either way, you are being unnecessarily disruptive by arguing nonsensically against some very knowledgeable people who are absolutely correct if my interpretation of this whole mess is accurate.

My suggestion is that you take a deep breath before your next post and then clarify your argument. If there is a misunderstanding, great. We'll get it cleared up. If you are in fact saying that when using a f/3.5 - 4.6 lens, the widest available aperture at the short end (f/3.5) is available to the user at the long end of the same lens by using Av mode, way too many people are paying too much money for fast glass when they could just be using Av mode and you would be very, very wrong.

EDIT: I want to be completely clear here. In my above paragraph, I am asking if you are saying that I can put a 3.5-4.6 lens on my camera, let's take the 10-22 for this example, dial in an aperture value of 3.5 @ 10mm, then zoom to the long end - 22mm and in Av mode, I would be able to dial in an aperture of 3.5 so the camera effectively has the same shutter speed and the aperture is letting the same amount of light in the camera at both the 10 & 22 ends? Is this what you are saying?

Maybe your initial comment was a mistake through unwillingness to admit it, this has snowballed into a compete mess? Who knows? Either way, I invite you to clarify your argument so that maybe we can end this and some of these guys here can post in a thread more worthy of the effort.

[DonSchap]

Look ... here is an "optimum" aperture shot ... that aperture was f/13 :eek: to make sure most of the object was in focus, front to back ... shot in Av Mode, with a 90mm f/2.8 lens.

30245
EXIF: 90mm - f/13 - 1/125 sec - ISO-400 - Aperture Priority


Sorry about my choice of subjects ... how tawdry, eh? ;)

Did I wan't f/2.8 ... no, I opted (<- operative word, here) for f/13.

The SONY A100 camera worked out the rest of the exposure for itself, using the built-in flash.

Had I stayed at f/2.8 ... I would get something that looks a lot like this:

30246
EXIF: 90mm - f/2.8 - 1/125 sec - ISO-400 - Aperture Priority


Note the unwanted f/2.8 bokeh ... definitely NOT "Optimum" Aperture.

[TenD]

http://www.uscoles.com/fstop.htm

http://www.paragon-press.com/lens/lenchart.htm

http://www.digital-slr-guide.com/maximum-aperture.html

http://www.dpreview.com/learn/?/key=aperture

Yes I know they are all wrong and you are right.

[Razr]

(SNIP)I seriously suggest you learn to read. "Optimum aperture" (or aperure as you quoted it) does not mean wide open at the arbitrary number of your choosing, it means wide open at the mathematical ability of the lens at the given focal length. Optimum and imaginary aren't the same word. Sorry."Optimum" aperture means "best" aperture at any given focal length with any given lens. Your unnecessarily convoluted (self-serving) asked and answered statement does not say that. There are two possibilities here. 1. You're mentally retarded and you need a great deal of help because of your learning disability, or 2. You have never owned an SLR or SLR lens. Either way, I feel sorry for you. Your post here will be reported to the admins. Finally, why would every lens manufacturer list their lenses as "f/3.5-5.6" or "f/2.8-4" if they could be used at f/3.5 or f/2.8 throughout the entire focal length? I am saddened that you do not know enough about lenses, lens markings or how lenses function in Av mode to even ask the proper questions.
Worse, you don't seem to comprehend that the markings denote the largest and smallest aperture settings.
They serve another purpose: to mark the f/stops for the photographer. What possible reason could there be aside from the fact that you're wrong I'm wrong for the way they mark their lenses? for them to inform people that at the telephoto length, they'll only be getting f/5.6? that makes no sense. Why wouldn't they just list their lens at the maximum aperture that you have found a magical way to invoke despite the fact that physics deem it impossible? "Asked and answered" as they say in court. "Maximum (and median and minimum) apertures" are attained in Av. and full manual mode throughout the zoom range.

[Rooz]

i doubt you've ever owned a camera or lens in your life. no one with practical experience with a dslr could possibly be this foolish.

someone please close this thread.

[Razr]

http://www.uscoles.com/fstop.htm

http://www.paragon-press.com/lens/lenchart.htm

http://www.digital-slr-guide.com/maximum-aperture.html

http://www.dpreview.com/learn/?/key=aperture

Yes I know they are all wrong and you are right.
Please, point me to the one that talks about "aperture priority"?

[Rooz]

Note the unwanted f/2.8 bokeh ... definitely NOT "Optimum" Aperture.

well...it's kinda optimum really cos it hides how ugly the a700 is. :p;)

[TenD]

Please, point me to the one that talks about "aperture priority"?

You have no understanding of the basics of aperture and f/stop, first learn the basics of what you are talking about. I haven't seen a single quote by you supporting your claims.

[TenD]

http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/aperture-priority.html

"Over the available range"
http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/950/aperture-priority.html

I suggest you read all of my links, and please supply one...one link that supports your "thesis".

[achuang]

The simplest way to prove your crazy theory to us Razr, would be to take a photo with a variable aperture lens (say f3.5-5.6) and take it at the telephoto end of the zoom and post the photo with exif intact and then you can show us how wrong the whole world is. If you're right then the aperture will be f3.5 even at the telephoto end of the zoom.

[Rooz]

i asked him to do that 6 pages ago. he won;t cos he doesn;t have a camera.

[achuang]

i asked him to do that 6 pages ago. he won;t cos he doesn;t have a camera.

I see, well that's unfortunate. Where's the fun in that? I was looking forward to being able to shoot my 55-200 lens at f4 all the way until 200mm.

[pas49ras]

Only if you are in "P" (PROGRAM) or "A" (AUTOMATIC) modes.
The aperture stays the same in "Av" and "M" (MANUAL) mode, no matter what focal length you choose, making any f/2.8-f4.5 etc. lens a "fast"-constant apeture lens throughout the zoom range.

This is the dreaded misconseption that started all the discussion...I have shot thousands of pictures in AV mode with a variable aperture zoom lens and as you zoom out the lens stops down..the aperture gets smaller. Its just the way that a lens is made. It would happen in any mode..AV mode just lets you select a aperture from the camera body, it can't (and will not) lock the aperture. The thing that is changing the aperture is the turning of the zoom ring.

[tim11]

Why would anyone pay more for Sigma 18-50 F/2.8 (me included) if one can just use Sigma 17-70 F/2.8-4.5 and 'lock' it at F/2.8 throughout the zoom range?
Maybe they don't know how to use A or M modes? LOL.
I can't wait to see what 'thesis' he will come up tomorrow morning and prove it's all possible.

[SpecialK]

I've already asked Jeff to close this thread about 4 pages back. I hope he will.

I suggest 2 things:

1. No one post another comment in this thread. We are wasting our time with someone who will never learn, nor wants to.

2. No one ever respond to RAZR in any other thread - ever.

Do not reply. Ever!

[r3g]

I suggest 2 things:

1. No one post another comment in this thread. We are wasting our time with someone who will never learn, nor wants to.

2. No one ever respond to RAZR in any other thread - ever.

Do not reply. Ever!


Oh your taking all the fun out of the internet.. Get real! :D:rolleyes::p

[fionndruinne]

That's right r3g! :(;):rolleyes:

It's funny how he seems to think there's a magic way of getting large-apertures out of variable-aperture lenses... as if no one else had figured out such an important concept, and weren't all using their 17-70mm f/2.8-4.5's for kicker cheap macro lenses at 70mm f/2.8.

It's true, though, the insults have gotten out of hand. Calling Razr all sorts of (apt) names isn't going to make him listen up.

But it's certainly been a chuckle or three. Makes little ol' DSLR-newcomer me feel all knowledgeable.:D

[Razr]

NO. YOU ARE WRONG. At full zoom of the lens in question (ie. sigma 17-70 f/2.8-4.5) only F/4.5 is available.

You are a bigger idiot than I previously thought you were since you keep denying you are wrong.I'll report you for your insult.

[TheObiJuan]

I've already asked Jeff to close this thread about 4 pages back. I hope he will.

I suggest 2 things:

1. No one post another comment in this thread. We are wasting our time with someone who will never learn, nor wants to.

2. No one ever respond to RAZR in any other thread - ever.

Do not reply. Ever!

I blocked him a while ago and then was excited to hear Razr was banned, apparently it was a temporary ban. He needs to be PERMANENTLY BANNED.

He is a troll--no doubt about it.

BTW, it's good to know that my Sigma 70-300 f/4-5.6 is really a 70-300 f/4 in Av mode!
Whoopee, who needs a Sigma 100-300 f/4 when I can have a Razr version of the 70-300 with f/4 for 1/4 the cost!! :rolleyes:

[Razr]

He has never used an SLR, or SLR lens. That's all there is to it. That or he's a troll. Let this discussion of 30 against 1 (very undereducated person) die. Razr is wrong, everyone else has more than chicken noodle soup for a brain. End of story.gratuitous insults get you reported.

[tim11]

I'll report you for your insult.

I normally don't insult people but you are excectional case. I'd be happily banned If you can grasp an understanding that:

For a Sigma 17-70, F/2.8-4.5, at full zoom of 70 mm the maximum aperture available is 4.5. Similar result can be expected from lenses with similar specifications. You have been wrong all along.

PS: FYI Not less than 10 guys who reply to you in this thread live and breathe photography and not than 3 are photography lecturers from colleges. As for me, I took up photography 72 hours only and I already know more about lenses than you who is a PRO. What happened?

[Razr]

OK, I'm really late into this thread but I had to come see what all these posts were about. I've always tried to be as polite as possible and avoid these controversies but enough is enough.

Razr, you are attacking everyone else's points Wrong: I first posited the brutal facts about aperture priority and they, like you-have taken the opposite course. --- but are either incapable or unwilling to define exactly where you stand. I did so on page 1. You might go back and read what I said before you make totally gratuitous accusations. Your posts, more and more, are taking on the life of some sort of virtual chameleon; very bizarre looking but somehow able to blend in with the background. Casting gratuitous aspersions or damning with faith praise gets you reported. If you have something to say about my position on Aperture priority-have at it. Otherwise, stop the personal attack. One of two things is going on. Either you are completely glib or you are completely inept when it comes to expressing yourself. That gets you reported. Either way, you are being unnecessarily disruptive by arguing nonsensically against some very knowledgeable people who are absolutely correct if my interpretation is correct. Apparently you too never or seldom used or were never taught the basics of photography else you would know everything I’ve said is about Aperture priority is 100% correct. (SNIP) If you are in fact saying that when using a f/3.5 - 4.6 lens, the widest available aperture at the short end (f/3.5) is available to the user at the long end of the same lens by using Av mode, way too many people are paying too much money for fast glass when they could just be using Av mode and you would be very, very wrong. Since you too don’t seem to have the proper grasp of aperture priority and what is an is not happening when the lens is zoomed, try these blurbs:
Aperture Priority
http://www.mir.com.my/rb/photography/glossary/terms_a.htm
An exposure mode on an automatic or autofocus camera that lets you set the aperture while the camera sets the shutter speed for proper exposure. If (when) you change the aperture, or the light level changes, the shutter speed changes automatically.
Apart from the sport or action arena, aperture priority is the most common & effective automatic preference in photography. It can also explained as automatic exposure system in which the lens aperture is set by the photographer, and the camera sets the shutter speed. Can be used in the stop-down mode with any lens that does not interfere with the metering system.
_________________________________________
And http://www.picturecorrect.com/photographytips/207/aperture_priority_depth_field.htm
Set your camera to “aperture priority”. Your camera’s manual will have simple directions on how to do this (it’s quite often just a matter of turning the dial on top). Once you have your camera on “aperture priority”, you will be able to select the aperture setting that you want[/COLOR], and the camera automatically chooses the correct shutter speed You will note that no matter what fanciful permutations you and others use, only the shutter changes to balance the exposure.
Think of it this way: as has been posited by others, the aperture AND the shutter changes in Av when the lens is zoomed.
If that were the least bit true, the camera would be operating in “P” mode, not Av.
EDIT: I want to be completely clear here. In my above paragraph, I am asking if you are saying that I can put a 3.5-4.6 lens on my camera, let's take the 10-22 for this example, dial in an aperture value of 3.5 @ 10mm, then zoom to the long end - 22mm and in Av mode, So far so good. I would be able to dial in an aperture of 3.5 There is where you are confused. First, I would never make such a ghastly error as to suggest such an impossible operation.
Next, in Av, you can only set one (1) aperture value at the time.
I wonder where you got the idea you could do differently? so the camera effectively has the same shutter speed and the aperture is letting the same amount of light in the camera at both the 10 & 22 ends? Is this what you are saying? Never said nor inferred such madness. What you suggested here (above) cannot be done in any case: two apertures on one lens: impossible and as I noted, not what I said but what you conjured up.
Read my first post in this thread (page 1) to find out what I actually said. Maybe your initial comment was a mistake through unwillingness to admit it, this has snowballed into a compete mess? Not a ”mess” of my creation. The “mess” ensued from people who don’t know how cameras work in Av mode. Either way, I invite you to clarify your argument so that maybe we can end this and some of these guys here can post in a thread more worthy of the effort. What they (and now I understand you) need is remedial photography lessons, specifically on what happens (inside the camera/lens) during an aperture priority shot.
As I noted, go to my first post on page 1 to see what I said.

[Razr]

Look ... here is an "optimum" aperture shot ... that aperture was f/13 (SNIP) First, that "optimum aperture" segue was not mine. Second, you exactly- precisely proved my point about "optimum" apertures. That is, the “optimum aperture” is lens and photographer specific, though for most subjects and shooting, usually two stops down from the maximum aperture is the so-called “sweet spot”.
So for my CANON FD 55mm asph. f/1:1.2, that would be about f/1.8. to make sure most of the object was in focus, front to back ... shot in Av Mode, with a 90mm f/2.8 lens.
(SNIP)Sorry about my choice of subjects ... how tawdry, eh? ;)
Did I wan't f/2.8 ... no, I opted (<- operative word, here) for f/13.

The camera worked out the rest of the exposure for itself, using the built-in flash.

Had I stayed at f/2.8 ... I would get something that looks a lot like this:
What you have demonstrated with the two shots is the “optimum” aperture for that lens varied according to the purpose you decided. Note the unwanted f/2.8 bokeh ... definitely NOT "Optimum" Aperture.Not for that deliberately lousy set up shot, which only proves you made deliberate choices in your effort to demonstrate which aperture/lens combination works best in any given (in your case-carefully selected) shooting venue.

[Razr]

I normally don't insult people but you are excectional case. I'd be happily banned If you can grasp an understanding that:

For a Sigma 17-70, F/2.8-4.5, at full zoom of 70 mm the maximum aperture available is 4.5. Similar result can be expected from lenses with similar specifications. You have been wrong all along. Any "automatic" variable aperture lens any maker since 1953 can be used in aperture priority mode, a mode which locks the aperture in place and thus, has to vary the shutter speed to balance the shot. PS: FYI Not less than 10 guys who reply to you in this thread live and breathe photography and not than 3 are photography lecturers from colleges. As for me, I took up photography 72 hours only and I already know more about lenses than you who is a PRO. What happened? "Pro" who also taught photography and learned the craft in the "dip and dunk" film era.

Your and the argument here has raged on as neophytes, still wet behind th ears, enter the craft.

[Razr]

Aperture_Priority_Basics

Since most of you have missed the import of aperture priority (perhaps because you never or seldom use that semi-automatic function) contesting me with your own convoluted mental and wildly off-beat mathematical calculations, I will leave this thread with this posting.

I do want you all to take note of what “aperture priority” is and what the aperture in a variable aperture does and (especially), what actually happens as a variable aperture lens set on Av is zoomed: i.e.: the camera actuates the shutter (not the aperture), making it faster or slower in order to balance the exposure: zooming in Av does not change the aperture (hole size, blade position-etc.).

Every one of these blubs below will say the same thing about aperture priority and incredibly, most of you will disagree, pointing out in your own foibles and meanly directed, widely broadcast misunderstandings of what I said and again, what the blurbs are saying.
Any sentient person can understand my “frozen in place”, “locked aperture blades” and my other informal ways to say you set the aperture (and what 100% of you have missed), the camera sets the shutter speed to balance the exposure = ”aperture priority”.
So with the aperture “locked”, the only thing that changes in “Av” mode is the shutter speed (and sometimes your ISO in order to balance the exposure at the chosen aperture.)
__________________________________________
Aperture Priority
By Vincent Bockaert

http://www.dpreview.com/learn/?/Glossary/Exposure/Aperture_Priority_01.htm

In "Aperture Priority" mode, the camera allows you to select the aperture over the available range and have the camera calculate the best shutter speed to expose the image correctly. This is important if you want to control depth of field or for special effects. Note that because of their high focal length multiplier, a shallow depth of field is often very hard to achieve with digital compact cameras, even at the largest aperture.

This article is written by Vincent Bockaert,
author of The 123 of digital imaging Interactive Learning Suite
Click here to visit 123di.com


Article ©1998-2007 Vincent Bockaert and dpreview.com, with permission
_______________________________________________
Aperture priority
From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Aperture_priority

Aperture priority, often abbreviated Av or A on a camera dial, is a setting on some cameras that allows the user to choose an aperture while the camera selects a shutter speed to match. The camera will ensure proper exposure. This is different from manual mode, where the user must decide both values, shutter priority where the user picks a shutter speed with the camera selecting the aperture to match, or program mode where the camera selects both.
The main purpose of using aperture-priority mode is to control the depth of field. Aperture priority is useful in landscape photography, where a narrow aperture is necessary if objects in foreground, middle distance, and background are all to be rendered crisply, while shutter speed is often immaterial. It also finds use in portrait photography, where a wide aperture is desired to throw the background out of focus and make it less distracting.
Another common use of aperture priority mode is to suggest how the camera should decide a shutter speed, without risking a poor exposure. In landscape photography a user would select a small aperture when photographing a waterfall, hoping to allow the water to blur through the frame. When shooting a portrait in dim lighting, the photographer might choose to open the lens to its maximum aperture in hopes of getting enough light for a good exposure.
In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures within the limits of maximum/minimum aperture for a given focal length of the lens. Commonly, lenses provide greatest resolving power with a relatively medium-sized aperture.
______________________________________________
Aperture Priority Mode
http://digital-photography-school.com/blog/aperture-and-shutter-priority-modes
(often it has a symbol of ‘A’ or Av’ to indicate it’s selected)
In this mode you as the photographer sets the aperture that you wish to use and the camera makes a decision about what shutter speed is appropriate in the conditions that you’re shooting in.
When would you use Aperture Priority Mode? - if you remember our tutorial on aperture you’ll see how the main impact that aperture had on images was with regards to Depth of Field (DOF). As a result most people use Aperture Priority Mode when they are attempting to have some control in this area. If they want a shallow DOF (for example in the shot to the right which has the flower in focus but the background nice and blurred) they’ll select a large aperture (for example f/1.4 - as in the example to the right) and let the camera choose an appropriate shutter speed. If they wanted an image with everything in focus they’d pick a smaller aperture (for example f/22) and let the camera choose an appropriate shutter speed (generally a longer one).
When choosing an Aperture keep in mind that the camera will be choosing faster or longer shutter speeds and that there comes a point where shutter speeds get too long to continue to hand hold your camera (usually around 1/60). Once you get much slower than this level you’ll need to consider using a tripod. Also if you’re photographing a moving subject your shutter speed will impact how it’s captured and a slow shutter speed will mean your subject will be blurred).
____________________________________________
http://www.earthboundlight.com/phototips/program-aperture-shutter-priority-manual-exposure.html
(SNIP) If you're game for learning how to take more control of exposure yourself, Shutter Priority and Aperture Priority are good choices. In each, you can pick one variable and the camera will pick a value for the other to yield what the camera considers to be an acceptable exposure. Thus, in Aperture Priority, you can choose any aperture you want in order to yield the depth of field you want, and the camera will pick the shutter speed. In Shutter Priority, the reverse is true. You pick the shutter speed to either freeze motion or intentionally blur it, and the camera will select an aperture to make the exposure come out what it feels is correct.
________________________________
Aperture Priority
http://www.mir.com.my/rb/photography/glossary/terms_a.htm
An exposure mode on an automatic or autofocus camera that lets you set the aperture while the camera sets the shutter speed for proper exposure. If you change the aperture, or the light level changes, the shutter speed changes automatically. Apart from the sport or action arena, aperture priority is the most common & effective automatic preference in photography. It can also explained as automatic exposure system in which the lens aperture is set by the photographer, and the camera sets the shutter speed. Can be used in the stop-down mode with any lens that does not interfere with the metering system.
_________________________________________
http://www.picturecorrect.com/photographytips/207/aperture_priority_depth_field.htm
Set your camera to “aperture priority”. Your camera’s manual will have simple directions on how to do this (it’s quite often just a matter of turning the dial on top). Once you have your camera on “aperture priority”, you will be able to select the aperture setting that [I]you want, and the camera automatically chooses the correct shutter speed
___________________________________________
You will note that not one blurb here (or anyplace else) mentions any foolishness about the aperture “Changing” due to this or that permutation or action like zooming.
In Av mode, the aperture (blades, size of hole-is/are) fixed and unless acted upon by human hands, are unyieldingly steadfast in their setting while the camera is in Av mode.

[tim11]

No one cares about Av principle right here... it's become irrelevant now. I don't care what quotes and theories you bring forth. You are wrong about the lens. My argument is that you are wrong about lenses.

You said it's possible to use a 17-70 F/2.8-4.5 lens at F/2.8 at full zoom. No pro who still think straight will say that. That's WRONG. Your attempt to divert the argument fails. Who do you teach? A bunch of sheep?

Neophyte? Getting on your nerve because of a newbie correcting you? You are dead WRONG and don't have a clue about lenses. I suggest you google for lenses for a change instead of Av.

[Rooz]

Aperture_Priority_Basics

Since most of you have missed the import of aperture priority (perhaps because you never or seldom use that semi-automatic function) contesting me with your own convoluted mental and wildly off-beat mathematical calculations, I will leave this thread with this posting.

I do want you all to take note of what “aperture priority” is and what the aperture in a variable aperture does and (especially), what actually happens as a variable aperture lens set on Av is zoomed: i.e.: the camera actuates the shutter (not the aperture), making it faster or slower in order to balance the exposure: zooming in Av does not change the aperture (hole size, blade position-etc.).

everyone gets what Ap means. what you don't understand is that Ap is limited by the lens' maximum aperture. if you are in Ap the camera will automatically adjust the aperture when using a variable aperture lens to the lens' maximum aperture without you ever touching it . try this on any camera and that is what will happen. period.

post as many lame arguments as you like, post as many links as you like but all of that information assumes that the reader has a grasp of one of the most BASIC concepts in photography and lens'. obviously you are not one of those people.

will you or will you not post the exif from a photo taken from a variable aperture lens taken at its maximum focal length to prove your absurd argument ? YES OR NO. the answer must be NO because it cannot be done.

[Prospero]

None of the articles posted by Razr support his view. In fact, some of them even support the view expressed by all of us. It is not explicitly said that the f-stop changes if you zoom in a variable apperture lens and you have selected the maximum aperture. Why would they? There's no point in stating the obvious...

I agree with the ObiJuan on permanently banning this idiot. Razr is obviously not the professional photographer he claims he is and all he does for this site is create unrest and confuse newbies.

[D Thompson]

Then would the Great & All Knowing One please tell me how in the @%*# I can possibly set my efs 10-22 f3.5-4.5 and be able to get f3.5 when I zoom to 22mm, because I sure can't figure it out and I have had the Canon 20D almost since the day it came out. And yes, I have a couple of decades experience and my oldest brother has been doing photography since I was born (1954) and neither of us agree with your rantings.

A)You tell me how this can be done and I will apologize for what I think about you.

B)You can choose to ignore this post and continue with your impossible thinking.

[tim11]

(SNIP)
You will note that not one blurb here (or anyplace else) mentions any foolishness about the aperture “Changing” due to this or that permutation or action like zooming. (SNIP)

Foolishness? Those are very basic blurbs that writers assume anyone with a camera (and a suggestion of logic) will realise once they have a camera in their hands. And you don't know they do change? That shows what rubbish photography teacher you are. Please don't teach your kids, if you have any.

You seem to know something about Av.. that's good. Now for the next lesson go to Lens Specifications Explained (http://www.overclockers.com.au/wiki/Lens_Specifications_Explained)

For your benefit, I quote here right from the bottom line:
"EF 100-400 F/4.5-5.6L IS USM : An Electronic Focus lens with a telephoto zoom range from 100 to 400mm, with a maximum aperture of f/4.5 at the short (100mm) end and f/5.6 at the long (400mm) end."

[tim11]

---Razr is obviously not the professional photographer he claims he is and all he does for this site is create unrest and confuse newbies.

It's for this reason I keep going... .... However,,,, I admit this forum has been too quiet. :D

[Nickcanada]

This is the most fun I've had in while. It is starting to get boring now though. I think we are coming at Razr in too many directions. Lets focus our questions to just one and do not get side tracked from the one question. Do not talk theory.

Simple question..... It's been asked before........


Razr

Put the camera on a tripod

Take a variable aperture lens,

put it in M mode

Select the largest aperture you can, that is the smallest F # (1.4 is a larger aperture opening then 2.8, get it?)

select the widest focal length (if you have a 17-70mm lens 17mm is the widest)

take a picture

Now take the zoom ring and twist it until you reach the longest focal length (that would be 70mm on a 17-70mm lens)

Did the aperture value change? Did the F # change? Report your findings please!

IF you still don't believe take a picture now while you are at the long end of the lens, your camera is on a tripod so it should not have moved!

Review the two photos! is one darker then the other? I'm willing to bet the one at the longer focal length is darker. Why? Because the aperture value has changed!


Please do not respond or converse with Razr until he completes his homework! We must work together folks! :p


P.S. Did I mention I was having fun!

[tim11]

This is the most fun I've had in while. It is starting to get boring now though. ----!

Now that his answers are predictable.. yeah... it's getting boring. Expect more Av blurbs. I don't mind reading lens spec for a change though.

Maybe Jeff should hire someone once in a while like our Professor Razr here to add some spice to this forum. It's been almost in coma state for quite a while now...

[TenD]

Razr all of your quotes give a great explanation of Aperture Priority, but many of them support what the entire board (except you) say. The key point you are missing is OVER THE AVAILABLE RANGE. A variable aperture lens ie. f/3.5-5.6 cannot support a constant aperture of f/3.5 and when zoomed in f/5.6 is all the lens can physically support.

Even if you had an old fashioned "dip and dunk" lens with an aperture ring the amount of light entering the lens would be equal to a smaller f/number when zoomed, no matter that the aperture ring is set to the largest aperture. The opening is only so big and only so much light can enter the lens.

I can't understand why you won't simply take a variable aperture lens and put it on your body, set the maximum aperture, zoom it in, and out and watch your aperture change to the maximum aperture available. The opening may not change, but the maximum amount of light will, effectively changing your maximum aperture. The newer AF electronic lenses transmit this to the body and the f/number changes to reflect this, physically the opening probably doesn't change, but the effective light entering the camera most certainly does.

[JTL]

Warning to all:

Razr's position is designed to try to people banned from the site.

He was recently temporally banned for his egregious behavior. This thread is his revenge.

Jeff Keller had the nerve to send me an email for "insulting" Razr when all I did was ask that he back up his b.s... and I got an "Infraction Point" charged against me. Did this happen to anyone else?

I've contributed money to this site in the past when Jeff was looking to do an upgrade and I'll tell you all this, it's a sad day when an out-of-control troll can get away with this sort of thing and long-time contributors are punished for trying to make sure GARBAGE INFORMATION doesn't get passed and challenging the purveyors of garbage.

Jeff Keller...unless you want this site to implode, open your eyes.

Maybe Jeff should hire someone once in a while like our Professor Razr here to add some spice to this forum. It's been almost in coma state for quite a while now...If more contributors than I got that insulting email form Jeff Keller, this place is danger of being a lot more comatose...I'm sure no one will take kindly to it. He's in danger of only being left with Razr at the end of this.

[JTL]

None of the articles posted by Razr support his view. In fact, some of them even support the view expressed by all of us.There is no "view" by all of us...there is only FACT. He is wrong. There is no debate.

I can't understand why you won't simply take a variable aperture lens and put it on your body, set the maximum aperture, zoom it in, and out and watch your aperture change to the maximum aperture available. The opening may not change, but the maximum amount of light will, effectively changing your maximum aperture. The newer AF electronic lenses transmit this to the body and the f/number changes to reflect this, physically the opening probably doesn't change, but the effective light entering the camera most certainly does.

Razr does not test for himself because either:

1. He doesn't actually own a camera and lens to test with

2. The postion he is taking is just to get people riled up and he actually does know the difference....but I doubt it highly.

[nqjudo]

OK, I am convinced. Razr either does not own an SLR, owns an SLR with no lenses or is simply trying to make trouble here. I asked a very clear and concise question and like with so many others, his goal was to evade all common sense and avoid answering.

My suggestion to everyone is that we drop this. It's not worth the time or the trouble and it's unbecoming to see such an important part of the active DCRP community get dragged into this nonsense by someone who wouldn't appreciate the help even if he were willing or able to understand it.

JTL - I did not receive such an email from Jeff but I haven't been as active in this thread as yourself. One thing that I learned from my years working for someone else is that no matter how wrong the guy in charge is, he can still make your life miserable. Just drop it. You have more than made your point and you are absolutely right so it's not worth pursuing. I have never had any direct contact with Jeff but I would hope that he would have the ability to see what is going on here and LOCK THE THREAD rather than start slapping people on the wrist.

[Nickcanada]

How come I never get emails!!!! I want to get banned too! I feel like I'm missing out. :(

[David Metsky]

Never argue with a fool; people may not be able to tell the difference.

[Nickcanada]

Never argue with a fool; people may not be able to tell the difference.

I like that. It's very true!

Also I agree you should never argue with the guy in charge, my boss is never wrong. ;)

[Prospero]

There is no "view" by all of us...there is only FACT. He is wrong. There is no debate.

Of course you are right about that, it's no debate, but just about fact here. Using "view" was just a poor choice of words on my part.

I don't see why you were sent such an e-mail. Your style of writing in this thread may have come across as a bit aggressive every now and then, but given the nonesense Razr keeps talking about it was definetly not uncalled for.

Nick, perhaps you should ask Coldrain for advice on how to get banned :D.

[Jeff Keller]

What is this, middle school or something? Is it possible to have a normal discussion here without all the personal attacks?