fgianni
Trainee Amateur
I'd like to hear from anyone that has used the CV 12mm heliar, at which aperture they started to see a softening effect due to diffraction, with such a wide lens I'd be wary of going beyond f8.
fgianni
Trainee Amateur
No one, really no one?
Alec
Amateur
I sure would like to have a first-hand experience of this lens !
Meanwhile, one opinion :
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0095iW
It might be outdated - at that time Al Kaplan seldom used his 15mm...
Meanwhile, one opinion :
http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=0095iW
It might be outdated - at that time Al Kaplan seldom used his 15mm...
Ron F
Member
Diffraction?
Diffraction?
When I first decided to buy a Leica (about 2 months ago) the first lens I bought (in fact, weeks before I bought the camera) was a brand new Voigtlander 12mm lens. I currently have 4 pictures posted in my gallery which may or may not be helpful in answering your question. The pictures taken inside the subway and inside Union Station were done at f5.6 and the pictures of the Smithsonian Castle and the wall were both done at f11. The curve of the outer two towers of the Castle was clearly because the camera was tilted a bit downward. All 4 of the pictures were handheld without a level and were taken on Kodak Gold 400.
I honestly don't know what diffraction is or what to even look for when discussing it, but if you want comments about the color, I can say that the color is nice and bold and that the images are quite sharp with pleasing contrast.
Alas, I've posted these pictures as I get ready to sell this lens. The only reason I've decided to sell it is that I find it a little too unforgiving when not held perfectly level and I'm a little impatient when it comes to composure.
I hope this helps.
Diffraction?
When I first decided to buy a Leica (about 2 months ago) the first lens I bought (in fact, weeks before I bought the camera) was a brand new Voigtlander 12mm lens. I currently have 4 pictures posted in my gallery which may or may not be helpful in answering your question. The pictures taken inside the subway and inside Union Station were done at f5.6 and the pictures of the Smithsonian Castle and the wall were both done at f11. The curve of the outer two towers of the Castle was clearly because the camera was tilted a bit downward. All 4 of the pictures were handheld without a level and were taken on Kodak Gold 400.
I honestly don't know what diffraction is or what to even look for when discussing it, but if you want comments about the color, I can say that the color is nice and bold and that the images are quite sharp with pleasing contrast.
Alas, I've posted these pictures as I get ready to sell this lens. The only reason I've decided to sell it is that I find it a little too unforgiving when not held perfectly level and I'm a little impatient when it comes to composure.
I hope this helps.
John Robertson
Well-known
I don't have the 12, but have used my 15 right down to smallest aperture without problem. There will be a slight fall off in definition but hardly noticible unless you are one of these who enjoys photgraphing lens charts!! 
yossarian
Well-known
There's a rule of thumb regarding diffraction, which is never use an aperture smaller than one-quarter of the focal length. Oops!
I borrowed a friend's 12 and shot tests on Velvia 50, and using a 22x loupe could find no appreciable difference from 5.6 through 11 (except, of course, for vignetting).
By 16 things began looking slightly less well defined, but the difference was not dramatic. This was essentially the same pattern I found with my 15mm.
I hope this illustrates that you'd have no worries with enlargements up to 16x20 at any aperture on this lens.
I borrowed a friend's 12 and shot tests on Velvia 50, and using a 22x loupe could find no appreciable difference from 5.6 through 11 (except, of course, for vignetting).
By 16 things began looking slightly less well defined, but the difference was not dramatic. This was essentially the same pattern I found with my 15mm.
I hope this illustrates that you'd have no worries with enlargements up to 16x20 at any aperture on this lens.
x-ray
Veteran
I know the 12 and 15 are completely different animals but I do own one of the early 15 Heliars. It's an exceptional lens for the 15mm focal length. I previously owned a Nikkor 15 3.5, 14 2.8 and Zeiss 15 3.5 for my 3003 rolleis. The 15 Heliar is the best of all of them in both contrast and resolution. Contrast is exceptional even when shooting into a light source. I've been curious about the 12mm but have not had a chance to try one.
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
http://www.rangefinderforum.com/photopost/showgallery.php?cat=5045
jdos2
Well-known
I can break out the books for the math... I believe a 12mm is competing CoC's with CoD's by f/8, but I'd have to again, do the math...