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Vignetting with wide-angle APS-C lenses - Why ?
The quotation below is taken from the test of a Pentax 14mm (35mm equivalent = 21mm) wide angle lens, posted on thehttp://www.photozine.de website..

"The DA 14mm f/2.8 is a dedicated APS-C lens and being a large aperture ultra-wide lens doesn't make things any easier regarding vignetting. At f/2.8 the lens produces a hefty amount of vignetting (~1.5EV) which will be visible in many situations. The situation improves a bit at f/4 but it takes f/5.6 till the problem gets fairly negligible.".

My question is:.

Why is it that so many of the APS-C w/a's suffer from vignetting (to a greater or lesser degree) ? For two decades I have used an SMC-Pentax A-series 24mm f2.8 lens on various Pentax 35mm SLR bodies. No vignetting with this 35mm format lens..

We put men on the moon close on 40 years ago, surely we are able to design w/a lenses for APS-C sensors that do better than they do ? .

Your comments would be interesting..

Dave..

Comments (8)

The shorter the f-length of a wide angle lens, the more difficult it is to design for eveness of illumination across the whole image field..

APS-C lenses are shorter than FF35mm equivalent ones, and part of the extra difficulty shows itself in more vignetting..

Also, for reasons associated with the approach angle of peripheral light rays, digital sensors have a tendency to make any vignetting that occurs show up more than with a film camera.Regards,Baz..

Comment #1

Australopithecus wrote:.

We put men on the moon close on 40 years ago, surely we are able todesign w/a lenses for APS-C sensors that do better than they do ? .

1. Cost.2. Size.3. Long back focus.4. Micro-lenses in front of photosites..

Charlie DavisNikon 5700, Sony R1, Nikon D300HomePage: http://www.1derful.infoBridge Blog: http://www.here-ugo.com/BridgeBlog/'Experience: Discovering that a claw hammer will bend nails.Epiphany: Discovering that a claw hammer is two tools...'..

Comment #2

Many thanks for the information gentlemen !.

I had wondered about this problem for quite a while. Be great if, ultimately, they sort it out as the 24 was my favourite prime..

Dave..

Comment #3

Australopithecus wrote:.

We put men on the moon close on 40 years ago, surely we are able todesign w/a lenses for APS-C sensors that do better than they do ? .

Haven't you been paying attention ???.

We only FAKED PHOTOS of men landing-on-moon 40 years ago..

(but maybe that even more specifically makes your point).

Thanks for reading .... JoePhoto.

( Do You Ever STOP to THINK and FORGET to START Again ??? )..

Comment #4

Australopithecus wrote:.

Many thanks for the information gentlemen !.

I had wondered about this problem for quite a while. Be great if,ultimately, they sort it out as the 24 was my favourite prime..

24mm was a TELEPHOTO ......

My favorite was a 14mm !!!.

(also had a 8mm fisheye, but didn't use it much).

Thanks for reading .... JoePhoto.

( Do You Ever STOP to THINK and FORGET to START Again ??? )..

Comment #5

Hey Joe !.

1. Since when was a 24mm (in 35mm format) a telephoto ? .

2. I'm a NASA freak and don't buy into conspiracy theories..

Have a good day..

Dave..

Comment #6

Australopithecus wrote:.

Hey Joe !.

1. Since when was a 24mm (in 35mm format) a telephoto ? .

(compared to 14mm).

2. I'm a NASA freak and don't buy into conspiracy theories..

(just JOKING .... of course I don't believe that).

HOWEVER ... There was a article in Popular Mechanics magazine back in 1965 or 66 where they made a case that the original RUSSIAN "space-walk" was faked..

They made a convincing case at the time; bringing out things like in none of the photos was the entire Russian-astronaut visible, and some of the shots you could see what appeared to be "wires" which were holding himi in place..

Exactly like they try to show now in the NASA photos, they pointed out discrepancies in about a dozen of the Russian-released photos..

I in no-way think the NASA photos were faked, but they could have been right about the early Russian space program..

Have a good day..

Dave.

Thanks for reading .... JoePhoto.

( Do You Ever STOP to THINK and FORGET to START Again ??? )..

Comment #7

JoePhoto wrote:.

I in no-way think the NASA photos were faked, but they could havebeen right about the early Russian space program..

We have since heard that the space walk was nearly a disaster. According to Wikipedia, Alexei Leonov's space suit inflated, and he had a whole lot of trouble getting back in to the capsule....

"" Leonov was one of the twenty air force pilots selected as the first cosmonaut group in 1960. His spacewalk was originally to have taken place on the Vostok 11 mission, but this was cancelled, and the historic event happened on the Voskhod 2 flight instead. He was outside the spacecraft for 12 minutes on March 18, 1965, connected to the craft by a five-foot tether. At the end of the 12-minute spacewalk, Leonov's spacesuit had inflated in the vacuum of space to the point where he could not reenter the airlock. He opened a valve to allow some of the suit's pressure to bleed off, and was barely able to get back inside the capsule. Leonov had spent some eighteen months undergoing intense weightlessness training for the mission.



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Regards,Baz..

Comment #8

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This question was taken from a support group/message board and re-posted here so others can learn from it.

 

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