Apature

[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.

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 [I]priority[/I]?

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....
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.

[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/sho...2&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....
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.

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.

[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.