Unknown horizontal marks on Leica M6TTL exposures in bright scenes

[jcherubino]

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I recently purchased a Leica M6 TTL second hand (SN 246914 if it's helpful) and I've been loving it but having ongoing and difficult to resolve issues with some horizontal markings even after multiple repairs and I am really hoping someone here is able to provide some insight into how I can resolve this problem.

Initially, the effect was quite bad and had some big distortion on the whole left hand side of the frame even in not particularly bright scenes. As there are a few samples and the photos are larger than the file limit, I've placed them all in a dropbox link here (see before_repair images). Seeing this, I discussed the issues with the previous owner who was very helpful, but had not seen the issues at all when he was shooting with it previously. He also hadn't been using the camera very much in the lead up to him selling it. I took the camera to Camera Clinic for repairs in Melbourne. The report from this repair entailed the technician 'straightening the distorted shutte light traps. adjust the shutter speeds. re-assemble and test'. 

After these repairs the effect was greatly reduced, however, I still noticed that there were some issues when shooting into bright light in particular (see after_first_repair images in the dropbox). Keen to get the issue fully resolved I took it back to Camera Clinic and discussed the issue with the technician. His theory was that the metal on the interior frame edges may have been partially removed so bright scenes cause reflected light off the frame edges resulting in the marks. Accordingly, he 'applied a dark mask to the frame edge' in the second repair.

Unfortunately when I was shooting in bright scenes again I noticed that the issue was still occuring much to my dismay (see after_second_repair image). 

I really love this camera and I am super excited to keep using but before I have some long stints of travel and shooting I'd really love to get the camera in full working order, especially as I am often shooting in bright scenes. If there is any insight or help anyone is able to provide in fixing the problem it woud be greatly appreciated! 

I'm very happy to provide any extra photos or details if it helps in diagnosing the issue as well

Cheers for reading,

Josh

[jaapv]

That suggests to me that the problem is still with the removed frame edges, making the light sealing problematic. I would discuss the issue with Camera Clinic  they are a competent firm. 

[jcherubino]

Yeah I’ll definitely have to take it back, was just hoping for some experience from someone with a similar issue in case I could suggest a repair strategy to Camera Clinic 

Cheers for the input in any case 

[stray cat]

Camera Clinic should be suggesting a repair strategy to you. They are an authorized Leica repair centre so they should be getting advice from Leica if whatever they've done hasn't fixed the problem.

I wish you best of luck with it. The M6TTL is a brilliant camera.

[jcherubino]

Yep, perhaps I misspoke earlier - I definitely trust Camera Clinic and they’ve been super helpful thus far, and are as you say an authorised repair centre.
However, I figured any input and experience with prior issues from Leica owners would help expedite the repair process

In any case, I’ll be taking it back to them as soon as I can and I’ll hopefully update this topic once the issue is found for others in the future.

[John Robinson]

Given that the stripes go all the way across the frames, I would suspect something is scratching the film.  Have you examined the film under a bright light?  If the scratches are on the back, look at the pressure plate.  If on the front, look at the ridge where the film comes out of the cassette.  The lines seem darker at the trailing edge (closest to the cassette).

[Doc Henry]

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.....  who scanned the negative for you ?  are these traits on the negative  ?

 

 

 

[jcherubino]

6 hours ago, Doc Henry said:

.....  who scanned the negative for you ?  are these traits on the negative  ?

Yep the traits are visible on the negatives as well. The photos have been a mixture of lab scans (from 2 different labs) and now I scan at home and still see the same issues across all of them. I have checked a few of the negatives on the light box and can definitely see the marks there physically as well.

7 hours ago, John Robinson said:

Given that the stripes go all the way across the frames, I would suspect something is scratching the film.  Have you examined the film under a bright light?  If the scratches are on the back, look at the pressure plate.  If on the front, look at the ridge where the film comes out of the cassette.  The lines seem darker at the trailing edge (closest to the cassette).

Yep that is a good idea, I had a look at the negatives on the light box but it's very hard to tell what side the marks are more distinct on. Looking at the pressure plate, it seems like it can slide a little bit left and right so perhaps that is part of the issue if it is putting too much pressure on the leading trailing edge of the film and marking it?

[giannis]

On 5/10/2022 at 4:14 AM, jcherubino said:

Yep the traits are visible on the negatives as well. The photos have been a mixture of lab scans (from 2 different labs) and now I scan at home and still see the same issues across all of them. I have checked a few of the negatives on the light box and can definitely see the marks there physically as well.

Yep that is a good idea, I had a look at the negatives on the light box but it's very hard to tell what side the marks are more distinct on. Looking at the pressure plate, it seems like it can slide a little bit left and right so perhaps that is part of the issue if it is putting too much pressure on the leading trailing edge of the film and marking it?

My guess is the shutter curtain - or some light sealing around it - started fraying, and the the stray frayed pieces are protruding into the shutter opening, blocking light from reaching the film and creating those shadows.

The reason you see it at the highest speeds, is because the slit that is the shutter opening at higher speeds, is narrower. This means, the same stray material covers a larger proportion of the slit and hence as the slit is travelling horizontally across the frame, it affects your exposure proportionately more than slower shutter speeds, making the effect more pronounced. Judging from what I see in the scans, this extra material is probably absolutely tiny to the naked eye - if you think about it the shadowy line's thickness is ~1/100 (or less) of the frame height, so the material causing it would be less than 24/100=0.24mm, a fifth of a millimetre or less. Under close examination with a loupe though the issue will be revealed.

[jcherubino]

On 5/11/2022 at 9:07 PM, giannis said:

My guess is the shutter curtain - or some light sealing around it - started fraying, and the the stray frayed pieces are protruding into the shutter opening, blocking light from reaching the film and creating those shadows.

The reason you see it at the highest speeds, is because the slit that is the shutter opening at higher speeds, is narrower. This means, the same stray material covers a larger proportion of the slit and hence as the slit is travelling horizontally across the frame, it affects your exposure proportionately more than slower shutter speeds, making the effect more pronounced. Judging from what I see in the scans, this extra material is probably absolutely tiny to the naked eye - if you think about it the shadowy line's thickness is ~1/100 (or less) of the frame height, so the material causing it would be less than 24/100=0.24mm, a fifth of a millimetre or less. Under close examination with a loupe though the issue will be revealed.

This sounds very promising - I really appreciate the detailed thought into the issue. I'll definitely suggest them to look into this when fixing up the camera and hopefully that solves the problem!

Thanks again