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Corner Issue on 35/2 Summicron


citizen.one

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I have an old Cron 35/2 serial # 2462xxx, Canada made,(don't know if it's a six or seven elements) and just tried it out on my M9.

I do get the same vignetting as on your picture. Doesn't matter whatever lens I choose in the menu! Doesn't matter if hood on or off! No filters used!

No vignetting to be seen when used on M6 or M7.

 

Can you try to force the frame to a not-35 one (28) and see if something different does happen ?

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Can you try to force the frame to a not-35 one (28) and see if something different does happen ?

 

Don't understand!

Do you mean "force" by using the manual lever instead of letting the lens choose the frame?

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I just tested with my Summicron ASPH. 35(on my M9) to compare.

Some visible vignetting is normal but the OP's samples look worse than I would expect and worse than my result.

Some other factors that may be involved (not to discount the other suggestions made in the replies already).

The OP's lens has natural vignetting of 2.5 stops which is quite a lot (but comparable to what the Summiluxes are doing in that focal length).

It would be worst at f/2 (The ASPH. has .7 stop less)

It will be much more obvious when you have a light plain background. The same effect may not be obvious or important at all in many photographs.

Of course with the M8 it was effectively cropped away and invisible.

I would suggest trying some more test shots stopped down and compare those. To be properly scientific you would need to shoot the same frames with a film M as well, on slide film without any mount so you can be confident that you will see the exact effect on the exposure (not an auto correction in printing) and with zero crop.

 

I suspect that you may find the result is much closer than memory has told you.

Also remember that Leica has long said that it is very difficult to adapt the 24x36 frme with M lenses and a sensor. There has to be some compromise, which of course is why we have displaced micro lenses to make it possible at all. The firmware will be correcting the vignette to some extent if you have the manual selection made. However the firmware corrections are NOT aperture specific and, according to Stefan Daniel, they are for the best case rather than the worst case (wide open) for each lens. This is to avoid overcorrection. I expect that we may see the firmware corrections adjusted for specific lenses in the future. The 18 is the most obvious example currently, but the wides will always be the most challenging. We may find that correction in post processing will continue to be the most practical for some lenses in their worst case situations.

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Can you try to force the frame to a not-35 one (28) and see if something different does happen ?

 

Just did a test forcing the 28 mm frame by using the Cron 35/2 (2462xxx).

I see no difference from using the 35 mm frame.

How should it make a difference?

Also tested the Cron 35/2 ASPH same way... no vignetting with 28 or 35 mm frame.

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Just did a test forcing the 28 mm frame by using the Cron 35/2 (2462xxx).

I see no difference from using the 35 mm frame.

How should it make a difference?

Also tested the Cron 35/2 ASPH same way... no vignetting with 28 or 35 mm frame.

 

A someway bizarre speculation I had in my mind... :o... I imagined there could be some firmware errors (originated at factory when loading it) into the "correction for 35" routines... something that instead of attenuating the std. vignetting was actually increasing it... declaring to the software that the lens is NOT a 35 could in case "skip" the bugged routine... oh well, thank you to have made this strange test... :)

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A someway bizarre speculation I had in my mind... :o... I imagined there could be some firmware errors (originated at factory when loading it) into the "correction for 35" routines... something that instead of attenuating the std. vignetting was actually increasing it... declaring to the software that the lens is NOT a 35 could in case "skip" the bugged routine... oh well, thank you to have made this strange test... :)

 

You are welcome.

Glad if it was of any help :)

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Well, just to post result :

 

In place of letting me calm down my friend found his camera doing the same weird stuff, even with 2/35ASPH, and with my IV serie Canada lens he had even worst than with mine. So next step is that in our local store will arrive another M9 and we'll test it then, anyway we'll contact Leica soon, we'll see how they'll react...

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Well, I only can say that the Summicron 35/2.0 asph simply does not vignette worth mentioning on the M9.

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enters M9 forum

 

...says "lens works great on my M8.2"....

 

exits quickly, stage right.

 

Jeff

 

PS...sneaks back in....

 

Sorry, couldn't resist. But, does make me wonder about my probable move to FF digital M at some point...don't remember these issues in film days. I'm curious to know cause/solution. Hope you resolve issue soon.

 

PPS....Jaap's post above makes me feel better

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@citizen.one: Why don't you post those pictures your friend took?

If it's not a lens fault (and that's supposed since you said the issue is not visible on a film camera), I really can't believe how can two similar cameras show the same problem with different lenses on a single specific FOV.

 

I tried once again, just to check, the 35 cron IV, 35cron ASPH, 35 Summarit and 35lux ASPH.

None of them showed that issue.

I still believe there must be a problem on a lens' element, or a filter/hood problem.

Apologize if you already tried that, I didn't carefully read the whole thread.

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It seems to be an astounding coincidence that the only two M9-Summicron combinations in the world to produce this phenomen have landed in the hands of two aquaintances.

 

To give this discussion hands and feet you should do two things:

 

1. Upload the relevant DNG files somewhere and make them available.

2. Contact Leica about this.

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The posted images look dramatically underexposed and seem to have had contrast boosted. Post processing can emphasize light falloff even in lenses that look fine in normal use.

 

I'd suggest getting the technical details up to snuff regarding exposure and making sure you are not adding any contrast or mid point shift to the image.

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That is right, Dan, and given the fact that all Summicron lenses vignette more than 2.5 stops, except Version III (2 stops) and the asph (1.8 stop), it might go a long way to explaining this.

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I experienced something similar last weekend on a mountain trip, have a look at the attached picture (not posted for artistic reasons, not particulairly interesting picture)

 

Picture taken with M9 and 35mm summicron version IV, Canada, early 1980's. Took four pictures in a row over a couple of minutes. All four shows same vignetting. Pictures taken five minutes earlier and five minutes later shows no sign of vignetting (camera switched off and on before and after the series with vignetting).

 

Have taken many pictures with the same lens both on the M9 and my M6, but never seen anything like this.

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