sonnar 50/1.5 vignetting

[Pherdinand]

Hi.

I have a thing that bugs me for some time already. I've shot a roll of slide film in my Contax, using the 50/1.5 sonnar, and on many of the frames there's a strong vignetting visible. Maybe i'm nitpicking, but i find it really annoying in some cases, i will post two examples. Other times it's fine, of course, like on the third image😀

Does anybody have a similar experience, or an idea about the reason? There's no separation or fungus or such on the lens, only minor cleaning marks and heavily dented filter ring which is straightened out more-or-less. I think i used no hood in this case, there was no sun only clouds. Some shots were wide open, some were close to wide open, certainly below f/4.

 

[Rich Silfver]

Haven't noticed it yet in the few rolls I've put through my Contax - but will look out for this in future rolls.

(Love the third shot)

 

[VinceC]

The lens design is close to 75 years old now. It vignettes. The light fall-off will be more noticeable when the lens is wider open and focused at specific distances. If the lens is optimized for mid-range focus (I think that's what I've heard) then light fall-off will be more noticeable at close focus than at mid-range focus.

 

[Pherdinand]

thanks Vince.
But i was surprised at the level of vignetting. Every lens does vignette, but i expected less.
Anyway.
I think the light falloff should be smaller at close focus, since the image circle gets larger. That's what I calculated once, some time ago, don't know how, anymore.
But i might be remembering the other way aroiund😀

I will check if it's the case with the sonnar 50/2 as well. I got one of those too.

 

[rvaubel]

You call that vignetting? Hah, thats nothing for use R-D1 users. I'll get 2 f stops of vignetting with my 15mm Heliar. Easy to fix with CR2 in photoshop though. I would asume if you are scanning your film that you could make the adjustments in PS. It would be a much bigger pain in the ass to make corrections in the wet darkroom( I know, been there).
This vignetting thing is going to be a big deal with the advent of the M8. Since rangefinder cameras use non-retrofocus designs for their wide angle lenses, vignetting is an unavoidable consequence. Us digital rangefinder users, all 100 of us on this forum, have been forced to deal with the issue much more than we did in the film days or even with DSLR's. However, it is not such a big deal with the introduction of vignetting sliders with most of the major raw converters.
My point is that if you are in a digital post poduction mode anyway, the solution is already at hand. The cool thing about the vignetting sliders is you can use older designed lenses without being totally concerned about how they vignette.

Rex

 

[Flyfisher Tom]

The lens design is close to 75 years old now. It vignettes. The light fall-off will be more noticeable when the lens is wider open and focused at specific distances. If the lens is optimized for mid-range focus (I think that's what I've heard) then light fall-off will be more noticeable at close focus than at mid-range focus.

I agree with Vince. At wide-open pretty much every lens vignettes. Even modern designed lenses do so. Your samples don't look much different than my CV 40/1.4 nokton did at wide open, so I think your lens is doing fine 🙂

 

[kbg32]

thanks Vince.
But i was surprised at the level of vignetting. Every lens does vignette, but i expected less.
Anyway.
I think the light falloff should be smaller at close focus, since the image circle gets larger. That's what I calculated once, some time ago, don't know how, anymore.
But i might be remembering the other way aroiund😀

I will check if it's the case with the sonnar 50/2 as well. I got one of those too.

The image circle - circle of confusion, should stay the same, no matter what the focus, close or far. Stopping your lens down 2-3 stops should take of the vignetting.

 

[Pherdinand]

I think depends on the focusing mechanism applied, but for these lenses where the whole lens moves forward to focus i think there is something happening w the size of the image circle.

Rex, ok, i would expect it from a wide or superwide but not from a simple normal lens. It is indeed correctable in PS, but i have no experience w that. ANd on the slides it looks plain ugly. 🙁

Anyway. Flyfisher Tom, that's ok then, i must say i'm happy to hear that the 40/1.4 nokton is vignetting the same way 😀 happy for my sonnar, of course.