M5: How to fix this frustrating light leak

[anonymous]

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Hey everyone!  I have been battling with a light leak in my M5 for about 7 months now.  The first image is an example of how it comes through to the center of the frame.  I’m seeing this on a small portion of my photos to varying degrees.

Tonight I went into a pitch black room with a flashlight and my M5 in bulb mode.  With the shutter open I could see light coming through around the left-top edge of the lens.  The other two images attached are where I was shining the flashlight (front) and where I could see the light coming through (back).

It makes sense to me now that this would only appear on a small number of my images — when the shutter isn’t open the leak has no effect on my negatives.  When the shutter does open, depending on the light situation around the camera it would vary in how much it affects the negative.

So now, the $1M question: how do I fix the leak?  It’s not a single pin point but seems to really be about 60º or so around the lens mount.  Thanks!

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[jerzy]

it looks like you found a way to reproduce the light leak - this is already half of success.
But I think it would be worth to reconfirm if this is really the source. Put a piece of black isolation tape in the place as marked below and check if you can still observe the light leak from the back. If  yes, than the light leak may come through the viewer window and rangefinder assy. If leak is not to be seen anymore than there are still 2 possibilities: lens or bayonett mount on M5. If you can eliminate the lens than you may try with painting black the bayonet ring in this place (with permanent marker, to have a thin layer of paint). If it will be the ring causing the leak than you will need to replace it

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[250swb]

There is a screw in the lens mount in around this area on the M5 and it may be worth investigating. So ask questions like is it the correct screw, is it loose, is it too tight and distorting the lens mount, is it too far below the surface of the mount and allowing light through (in a similar way that the coding window can on digital Leica's), and maybe the key question 'is there a also screw in the corresponding place on the lens flange' which may also contribute to the leak by being well below the surface of the flange. If the answer to the last two questions is 'yes' I'd try covering the screw head over in a wax putty (like the type used to seal over the topmost screw head in the body mount) so the putty is flush with the surface, and do this on the lens as well. 

Edited November 9, 2023 by 250swb

[hmzimelka]

The light leak from that portion of the mount tends to show as a bow in the bottom right side of your images. I don't think the light leak seen on your image is caused by the light leak you're observing with the flash light. 

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The light leak at the mount is a problematic source of light during long exposures on M cameras, and I use a hair scrunchy over the lens and cover the mount to avoid light leaks for the 60+ second exposures during daylight. 

Perhaps rule out that mount leak by using a scrunchy, and then take the next step to finding that leak. I however don't think its from the mount.

 

 

Edited November 9, 2023 by hmzimelka