CV Nokton 50/1.5 vignetting?

denishr

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I've just got a first color roll shot with Nokton 50/1.5 back from the lab - there's noticeable vignetting in the corners!

I took some shots of my son with a white wall in the background, and I can clearly see vignetting in the corners. I thought it could be a UV filter I put on the front (rather thick rim), but, when checked on the camera with the back open, it doesn't seem to be the cause.

Once again, I tried to find some info on the Web, and found that Erwin says it vignettes... 🙁

Anyway, I like the shots, and I really like the images from Nokton... The vignetting doesn't bother me that much, but I'd like to know if others had similar experience.

Details: Leica M6, Nokton 50/1.5, Fuji Superia 100 Vulgaris, shot mostly on 1/500 and 1/1000 and wide open (f/1.5 and some on f/2).

Cheap scans from the lab...

Denis
 
rover said:
Does it seem to you that the vignetting is more on the right than left side of the image?

Yes, but it could be due to the fact that the left side was better lit - i.e. the right side of image was in partial shade.... on all three photos 🙂
In short, the background was not evenly lit - but those shots sure look like the lens is vignetting.
As I said, it does not bother me too much, but I'd just like to know if others noticed the same thing with Nokton...

Sorry for the shots - those are just quick snaps, nothing to really show, except as an illustration of the problem.

Maybe I should just take a few shots of evenly lit white wall without filter or shade (it's the original Nokton shade.).

Denis
 
I haven't really noticed it w/the CV 50/1.5 Nokton, but, to varying degrees, it's a characteristic of every high-speed (f/1.5 & faster) lens I've encountered. IME, I normally use the largest apertures in "available darkness" situations where vignetting or light fall-off are generally not noticeable; it wouldn't surprise me if lenses were designed w/such factors in mind.
 
I've not noticed it at all, at any aperture, with my lens.

That doesn't mean it's not happening, I guess, it just means I don't notice it! 😛
 
I dont have a Nokton and can't make direct comparisons. But looking at the photos does raise one question, was there a lens hood on at the time?

I had a similar vignettingproblem resulting from a lens hood that was just slightly too long for the lens. It would only show up when I focussed on near objects.

Just a thought.
 
The mystery should be solved in a day or two - just shot a couple of shots of a blank, evenly illuminated white wall - with no filter or hood. I wonder if I'll notice any vignetting on those shots....

Denis
 
denishr said:
I've just got a first color roll shot with Nokton 50/1.5 back from the lab - there's noticeable vignetting in the corners!

Cheap scans from the lab...

Denis

Denis,
I own and use this lens since 3 years and I tell you there is something wrong , but this has nothing to do with the design of the lens.

This is not vignetting but light fall off ( much more at the rhs !) of about 3 f stops, and that's looking worse than a 4,5/15mm Heliar !!
It could be a lab fault (do the negs look the same ? ) at the printing process or you really caught a really sick Nokton sample. Maybe the stop blades to not work properly ?

If this were the Nokton's standard preformance nobody ever would have bought it. I don't dare to send you any of my Nokton shots to prove it because I have not in mind where and how much I cropped each pic for the web presentation. But let me assuree I never ever have seen such an effect at my lens.

And don't try to get reliable informations about CV glass from Erwin Puts' site, can't work, wrong adress. He is the tip of the spear in Leica's underground marketing ! 😀

Best,
Bertram
 
Have to agree with Bertram especially on the comments by Herr Putts!!! I've never noticed vignetting with my own Nokton, you say the UV filter mount was quite thick; did you then screw in the hood on top of that?? If so could be the problem. Putts never has anything good to say about any lenses which don't come from Solms!! Sorry but its true.
 
Well, regardless of what Putts says, I got another roll developed, and the results are similar 🙁
Dang!

I'll have to shoot a short roll of B&W film, with various f-stop settings, carefully recording all settings, no filters, no hood, and see what happens.

I just can't trust the lab's scans 🙁

Here's another (small) shot, which shows the same problem, this time definitely without hood or filter...

Denis
 
Hmmm, sad to see that this is happening. The Nokton has been an excellent lens for me... Good luck with your tests, I hope this issue can be resolved soon.
 
Hi,
just for fun i made two shots wirth each of my CV's last summer.
One full open, the other closed.The attached ...203 is the opened,
the ...204 is the closed. Unfortunately there isn't white wall in-picture
, but i can't see such a vignetting.

...I don't know wether it helped or not...

Cheers,

nemjo
 
Denishr: I've had similar experiences; I think the problem is with the scanner. I get some pictures with evident vignetting effects with pictures taken with my 50mm Summicron! I notice this effect specially when I've underexposed a little bit; I can't explain it, but I experience the same thing as you do.

Now, it is very possible that you may have a Monday morning QA copy, like me. It does happen. I suggest one thing (which is what I'm going to do too): try a few of the same shots but with a little bit of overexposure, and see if you get the same effect. I only see this effect between f/2 and f/2.8 when underexposed *and* when scanning with a bit of heavy color-cast and histogram correction during scan-time. I wonder if your conditions are the same.

Regards
 
To illustrate my point: this was purposefully underexposed; Fuji Provia 100F, 50mm Summicron (latest version); I exaggerated levels and curves in Photoshop to show the vignetting effect...
 
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The B&W test roll is drying... I'll see later this evening or tomorrow morning what happened with B&W film, and probably scan the negs later... The B&W test should provide more info, since there are no unknown variables in the process 🙂

Denis
 
Yep, it's vignetting allright 🙁
Most pronounced at f1.5, but still slightly visible at f2 and f2.8. It about disappears at f4.
Attached is an example at f1.5....
Well, I guess I'll just have to live with it. I shoot mostly B&W, so it's not a big deal - I just have to keep that in mind and adjust accordingly - either after scanning, or just dodge the corners during enlarging.
Otherwise, I like the lens. It's on the heavy side, but otherwise quite capable.

Denis
 
I went back through some of my old Nokton shots to see if any showed vigenetting. None did but I can only guess which were shot full opened.
 
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