[archaeodude]

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Hi Fellow Film Photographers,

I have recently developed the first roll of 120 film I put through an old Yashica 635 twin lens reflex camera I acquired. The camera seems to be in pretty good working order, aside from the fact that the shutter sticks on its 'slow' speeds (1/30th of a second and slower). However, the shutter works fine on the 'bulb' setting and at all speeds 1/60th of a second and faster.


I was pleased with the performance of the lens and mechanics of the camera, but all the frames suffered from an apparent light leak (at least I think it is). Please see the attached scan for an example.

Does anyone know how to diagnose the light leak problem? And how to fix it?

From cursory research online, I wonder if the problem could be:

1. Light leaking in through the door of the film chamber?
2. A light leak related somehow to a shutter problem?
3. 'User error' that may have resulted in a light leak when I loaded or unloaded the roll of film?

I'm completely new to film photography, and I have novice camera repair skills. Please could this excellent community proffer some advice and guidance?

Best Wishes,

Andrew

Attached Images

 

[JohnMc]

Please find a way to show the film strips including the border/edges and details of the processing.

[Alex645]

IF the light leak appears in the same area of multiple frames, then it's probably a light leak in the film chamber door. The lens when recording the image onto the negative will flip the image both vertically and horizontally, so if the light on the neg/print shows up in the top right corner, the leak is coming from somewhere in the bottom left of the door as you hold the camera with the lens facing forward.

Inspect the inside of the door for a dent or missing foam etc. The pressure plate should be parallel to the back.

Another possibility is that leaf shutter is 'sticking' and not closing completely. It may just need to be "loosened up" a bit. Without film, just take lots of 'shots' so that the shutter goes through many operations and that may loosen up the blades enough.

If the light leak appears in different areas of the negatives, then that could be 'user error', but from the one example you posted, it doesn't look like that.

[photoptimist]

The first rule for light leaks is:
1a) if the image of the leak is strongly confined to the exposed frame, then the source of the leak probably comes from the lens-side of the camera
1b) if the image of the leak covers the borders and gaps outside the exposed frame, then the source of the leak probably comes from the back-side of the camera

The second rule is:
2a) if the image of the leak is on the bottom of the exposed frame, then the source of the leak probably on the top of the camera
2a) if the image of the leak is on the top of the exposed frame, then the source of the leak probably on the bottom of the camera

The third rule is:
3a) if the image of the leak spreads all across the exposed frame, then the source of the leak probably in the door or hinge.
3a) if the image of the leak spreads along the edge of the exposed frame, then the source of the leak probably on the edge of the camera.

Finally, tracing a leak means thinking like a photon (which is a useful skill for any photographer!). That means thinking of all the place light might get in, the path it takes, what other things in the camera might block the light, and where it ends up on the film.

[archaeodude]

Please find a way to show the film strips including the border/edges and details of the processing.

These may not be great photos, but you can see the light leak in the lower left corner of each frame of the negative strips. It appears as a blackish splotch and is particularly visible near (but perhaps not within?) the gaps / spacing between frames.

As for the processing, I can't provide full details because I sent the film off to be developed at a local photolab. The filmstock is Fomapan Action 400, and I did not ask the photolab to push or pull anything, so I assume the processing was usual B&W fare.

---------- Post added 03-10-22 at 12:15 PM ----------

IF the light leak appears in the same area of multiple frames, then it's probably a light leak in the film chamber door. The lens when recording the image onto the negative will flip the image both vertically and horizontally, so if the light on the neg/print shows up in the top right corner, the leak is coming from somewhere in the bottom left of the door as you hold the camera with the lens facing forward.

Inspect the inside of the door for a dent or missing foam etc. The pressure plate should be parallel to the back.

The 'seals' are actually some mildly decaying wool around the film door. But it all looks to be in relatively good shape, aside from one small section. Could be the culprit...

Another possibility is that leaf shutter is 'sticking' and not closing completely. It may just need to be "loosened up" a bit. Without film, just take lots of 'shots' so that the shutter goes through many operations and that may loosen up the blades enough.

I'm starting to wonder if sticky shutter blades may actually be the problem, given my other difficulties with the slower shutter speeds (1/30th second and slower).

If the light leak appears in different areas of the negatives, then that could be 'user error', but from the one example you posted, it doesn't look like that.

We can rule this out, I think!

---------- Post added 03-10-22 at 12:18 PM ----------

The first rule for light leaks is:
1a) if the image of the leak is strongly confined to the exposed frame, then the source of the leak probably comes from the lens-side of the camera
1b) if the image of the leak covers the borders and gaps outside the exposed frame, then the source of the leak probably comes from the back-side of the camera

The second rule is:
2a) if the image of the leak is on the bottom of the exposed frame, then the source of the leak probably on the top of the camera
2a) if the image of the leak is on the top of the exposed frame, then the source of the leak probably on the bottom of the camera

The third rule is:
3a) if the image of the leak spreads all across the exposed frame, then the source of the leak probably in the door or hinge.
3a) if the image of the leak spreads along the edge of the exposed frame, then the source of the leak probably on the edge of the camera.

Finally, tracing a leak means thinking like a photon (which is a useful skill for any photographer!). That means thinking of all the place light might get in, the path it takes, what other things in the camera might block the light, and where it ends up on the film.

Thank you so much for spelling everything out so well for me! As mentioned, I'm new to film photography, so I'm still trying to learn the fundamentals. Your details will certainly get me thinking!

In general, I'm starting to think the leak may be solved by [1(a)] of your above list!

[JohnMc]

The leak is not likely 1a, and is probably a seal on lower left corner if my guess about orientation is correct. Leak/fog appearance can vary based on ambient light and duration. Some of the frames appear to be fogged over broader area - the border or clear area should be consistent for the whole roll some appears to be fogged over the length of the frame - that could be shadow on the posted pic, but... you can test/locate by using opaque tape over the suspected offending spot(s).

[FozzFoster]

I expected my MX had light leak issues.
I bought a pack of little lights and placed two of them on each side of the camera.
Lystin 30 Pack LED Party Lights Decoration Light Mini Submersible Waterproof Party Lights for Paper Lantern Balloon Wedding Halloween Christmas Party Festival (Colorful) : Amazon.ca: Tools & Home Improvement
Turn out all the lights (under a blanket or whatever) and observe the camera from every angle.
I found where my light leak occured and was able to fix the leak.
Light Leak Proof Sponge High Density Foam Film Camera Replacement Light Seal Foam with Tongs for 120 135 Film Camera Large Format Camera Film Camera Accessories : Amazon.ca: Electronics

[Alex645]

Seeing the film is also fogged between frames makes me think it is most likely to be the film door. I can't imagine a light leak from sticky leaf shutter could reach that area of the film consistently.

[MadBill]

What I have done in the past with a camera with a light leak is position unexposed film from once around the take up spool to once around the supply spool and then let the camera sit around for a few days. With a TLR, starting with a fresh roll and with the camera covered with a dark cloth advance to frame #2. After leaving the camera exposed to light for a few days without taking any pictures, again cover the camera (except for the red window obviously) advance the camera to frame #5. You can then take the remaining photos as normal. When you get the processed film back position it in the camera with frame #2 in position. Any dark spots on the film indicate the location of of a light leak. I am not familiar with the Yashica 635. If it has a red window it should be covered with black tape except when advancing the film.

[archaeodude]

The leak is not likely 1a, and is probably a seal on lower left corner if my guess about orientation is correct. Leak/fog appearance can vary based on ambient light and duration. Some of the frames appear to be fogged over broader area - the border or clear area should be consistent for the whole roll some appears to be fogged over the length of the frame - that could be shadow on the posted pic, but... you can test/locate by using opaque tape over the suspected offending spot(s).

I'll give some tape a try on the next roll - hopefully it will fix the problem!

I expected my MX had light leak issues.
I bought a pack of little lights and placed two of them on each side of the camera.
Lystin 30 Pack LED Party Lights Decoration Light Mini Submersible Waterproof Party Lights for Paper Lantern Balloon Wedding Halloween Christmas Party Festival (Colorful) : Amazon.ca: Tools & Home Improvement
Turn out all the lights (under a blanket or whatever) and observe the camera from every angle.
I found where my light leak occured and was able to fix the leak.
Light Leak Proof Sponge High Density Foam Film Camera Replacement Light Seal Foam with Tongs for 120 135 Film Camera Large Format Camera Film Camera Accessories : Amazon.ca: Electronics

This seems like an excellent idea - I'll try to do a test like this!

Seeing the film is also fogged between frames makes me think it is most likely to be the film door. I can't imagine a light leak from sticky leaf shutter could reach that area of the film consistently.

Duly noted - I would be happier if the leak is coming from the film door, as I think that would probably be an easier fix than the shutter...

What I have done in the past with a camera with a light leak is position unexposed film from once around the take up spool to once around the supply spool and then let the camera sit around for a few days. With a TLR, starting with a fresh roll and with the camera covered with a dark cloth advance to frame #2. After leaving the camera exposed to light for a few days without taking any pictures, again cover the camera (except for the red window obviously) advance the camera to frame #5. You can then take the remaining photos as normal. When you get the processed film back position it in the camera with frame #2 in position. Any dark spots on the film indicate the location of of a light leak. I am not familiar with the Yashica 635. If it has a red window it should be covered with black tape except when advancing the film.

This sounds like a very systematic approach to diagnosing the leak. Perhaps I will give it a try! As for a 'red window', the Yashica 635 does not have one (you can see good photos from all angles here: Yashica-635 - Learn more the Japanese medium format camera).

Thanks for all the helpful responses. It may take me a few weeks, but I'll do my best to follow up on this thread with a report about my (hopeful) solution and the outcome of the next roll!