Apature

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

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Originally Posted by Razr

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.)

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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.

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Originally Posted by 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_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 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.

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Originally Posted by Razr

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.

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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_se...0_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_se...8-35/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.

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Originally Posted by Razr

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.

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

Ray.

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Originally Posted by Ray Schnoor

"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.

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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. :)

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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:

Quote:

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Originally Posted by Razr

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.

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How about this?:

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Originally Posted by Razr

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

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Oh yes you did my friend...read it again...and again...and again...you're never getting away from this one...

Quote:

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Originally Posted by Razr

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.

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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).

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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.

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

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:

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

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Originally Posted by Razr

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

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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.

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Originally Posted by 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

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No test needed: and here's why:

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From Wikipedia:
"In addition, aperture priority mode allows the photographer to force the camera to operate the lens at its optimum apertures.

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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.

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