Mysterious F100 light leak.

fotoobscura · Oct 22, 2018

I bought a Nikon F100 about a month ago and ran a test roll (portra 800) through it. Looked fine so I loaded another roll (trix @ 1600). That roll had light leaks coming from the bottom of the roll reaching about half way up the frame- basically ruined. The next roll same thing (portra 160) but not quite as bad. The roll after that had NO problem (portra 400). I shot two more rolls (both portra 800 @ 1600) and both rolls experienced the same 'effect'- The light leak started bad at the first frames and by say, frame 7 or 8 there was no longer a problem. These last two rolls I covered up the bottom part of the door seal with electrical tape, where the leaks appear to be coming from- if the door was leaking light I'd have guessed it should have been resolved- but alas, no! The camera looks and feels mint- the door closes fine. One thing I did notice is that the camera burns too many initial frames before "1". Usually it's closer to three.

I load the film the same way every time- I've been shooting Nikons for 25 years. I can't figure out the logic- Perhaps the lenses? It's definitely not my changing bag or loading. CLA? The thing seriously looks mint.

Thanks

Sirius Glass · Oct 22, 2018

Is the leak on the top or the bottom of the negatives? That will give an idea on which side of the door and the ends to look for the problem.

jim10219 · Oct 22, 2018

How are you developing them? Is it in a Patterson tank? Those can cause a similar light leak. I'd think, just like you, that covering up the seam with some electrical tape would have solved the issue if it was a light leak from the camera back. You might try covering up all of the door seals, or at least check the seals themselves for evidence of wear. Light can bounce around a bit, so it's possible that you could have a light leak on top that misses the film and bounces off something on the bottom, making you think the light leak is down there. You might even want to take the camera into a darkroom, remove the lens and set it to bulb mode and trigger the shutter and hold a light up to the lens mount hole and see if you can see any light leaking out the back.

Or, since it's an older camera anyway, just replace all of the light seals for good measure and then see if that takes care of the issue. If not, at least you'll have that taken care of. I always replace the light seals on any film camera I buy. At least half of them have light leaks when I get them, and the other half aren't far away from developing them. Plus, I buy the foam in sheets and cut them down myself, so it's fairly cheap and usually only takes me an hour at most. That also gives me an opportunity to thoroughly clean the camera, and get to know it a bit better before taking it out on a test run. It's part of my ritual.

BMbikerider · Oct 22, 2018

jim10219 said:
How are you developing them? Is it in a Patterson tank? Those can cause a similar light leak. I'd think, just like you, that covering up the seam with some electrical tape would have solved the issue if it was a light leak from the camera back. You might try covering up all of the door seals, or at least check the seals themselves for evidence of wear. Light can bounce around a bit, so it's possible that you could have a light leak on top that misses the film and bounces off something on the bottom, making you think the light leak is down there. You might even want to take the camera into a darkroom, remove the lens and set it to bulb mode and trigger the shutter and hold a light up to the lens mount hole and see if you can see any light leaking out the back.

Or, since it's an older camera anyway, just replace all of the light seals for good measure and then see if that takes care of the issue. If not, at least you'll have that taken care of. I always replace the light seals on any film camera I buy. At least half of them have light leaks when I get them, and the other half aren't far away from developing them. Plus, I buy the foam in sheets and cut them down myself, so it's fairly cheap and usually only takes me an hour at most. That also gives me an opportunity to thoroughly clean the camera, and get to know it a bit better before taking it out on a test run. It's part of my ritual.

As far as I am aware the F100 does not have light seals as such. There is just an extra deep baffle.

jim10219 · Oct 22, 2018

BMbikerider said:
As far as I am aware the F100 does not have light seals as such. There is just an extra deep baffle.

You might be right. I don't own one. And I don't know if it would be a good idea in his case, but I have put foam light seals into cameras that didn't originally come with them. I don't make it a habit, but sometimes an old camera that never had light seals, like my David White Stereo Realist, will leak a bit of light. The easy solution is just to install some very thin foam or velvet tape. You have to be careful with it though. You don't want to make the camera too hard to close and cause the body to warp.

Anyway, if it didn't originally come with light seals, I wouldn't just go installing them first.

shutterfinger · Oct 22, 2018

Seal around the film confirmation window bad. Tape over that window to confirm.

BMbikerider · Oct 23, 2018

If part of the way though the film the problem disappears then it isn't the camera! If it were the camera the problem would exist for the full length of the film. Think of looking elsewhere, as has been suggested it may be the developing tank, what type/make are you using?

I had to replace a JOBO central spindle recently because it was cracked and a small piece missing at the top below where the lid fits. I did not have a problem but that may be the cause.

I now have modified a stainless 35mm tank to take the JOBO magnet as well and these as you may know do not have a central spiral so eliminating another possibility

fotoobscura · Oct 23, 2018

Sirius Glass said:
Is the leak on the top or the bottom of the negatives? That will give an idea on which side of the door and the ends to look for the problem.

Bottom. See attached.

fotoobscura · Oct 23, 2018

BMbikerider said:
As far as I am aware the F100 does not have light seals as such. There is just an extra deep baffle.

Correct.

fotoobscura · Oct 23, 2018

shutterfinger said:
Seal around the film confirmation window bad. Tape over that window to confirm.

Interesting theory but would the explain the light leak going away after some frames?

fotoobscura · Oct 23, 2018

I think your first line is closest to the reality of what's going on- perhaps developing gear is causing the light leak. This would validate the fact that the light leak is intermittent as well as possibly explain why the leak starts out worse at the beginning and fades away later (the leaking tank is only leaking the 'exposed' frames)- that is, the earliest frames that are in the reel are on the outside. The end of the roll is in the middle of the reel and more protected from the leak by the existing film.

With all of the aforementioned rolls I used a one roll and two roll developing tank- Light leaks pervade using both tanks- The only commonality here is the reels of which I used for developing all of the film. They are fairly old (but sturdy) Omega plastic reels. That said, the state of a reel couldn't possibly impact the film getting unwanted light, could it?

I did cover up the rear (bottom) of the camera where the light appears to come from with electrical tape- It may have 'helped' but I believe that's a red herring as these last rolls saw the film 'losing' the light leak as frames went on. There aren't light seals per-se on the F100- It's a one piece construction which I guess you would call recessed baffles.

Thanks

jim10219 said:
How are you developing them? Is it in a Patterson tank? Those can cause a similar light leak. I'd think, just like you, that covering up the seam with some electrical tape would have solved the issue if it was a light leak from the camera back. You might try covering up all of the door seals, or at least check the seals themselves for evidence of wear. Light can bounce around a bit, so it's possible that you could have a light leak on top that misses the film and bounces off something on the bottom, making you think the light leak is down there. You might even want to take the camera into a darkroom, remove the lens and set it to bulb mode and trigger the shutter and hold a light up to the lens mount hole and see if you can see any light leaking out the back.

Or, since it's an older camera anyway, just replace all of the light seals for good measure and then see if that takes care of the issue. If not, at least you'll have that taken care of. I always replace the light seals on any film camera I buy. At least half of them have light leaks when I get them, and the other half aren't far away from developing them. Plus, I buy the foam in sheets and cut them down myself, so it's fairly cheap and usually only takes me an hour at most. That also gives me an opportunity to thoroughly clean the camera, and get to know it a bit better before taking it out on a test run. It's part of my ritual.

fotoobscura · Oct 23, 2018

Here's another one 16 frames in on the same roll- zero light leak.

fotoobscura said:
Bottom. See attached.

fotoobscura · Oct 23, 2018

I like your logic! Omega reels, not sure the tanks- They're both fairly old though- I have a one reel and two reel tank. The leak shows up on both. In a previous reply the reason why I like this theory the most is that this would feasibly explain the theory that the leak goes away after time as the earliest frames are the most susceptible to the light in the tank. On the other hand this would not in fact explain why the light leak is only pervading the bottom of the frames only. Note that I have developed an entire roll with zero light leaks in the middle of developing other rolls with light leaks (using the same tank).

BMbikerider said:
If part of the way though the film the problem disappears then it isn't the camera! If it were the camera the problem would exist for the full length of the film. Think of looking elsewhere, as has been suggested it may be the developing tank, what type/make are you using?

I had to replace a JOBO central spindle recently because it was cracked and a small piece missing at the top below where the lid fits. I did not have a problem but that may be the cause.

I now have modified a stainless 35mm tank to take the JOBO magnet as well and these as you may know do not have a central spiral so eliminating another possibility

fotoobscura · Oct 23, 2018

Bottom.

Sirius Glass said:
Is the leak on the top or the bottom of the negatives? That will give an idea on which side of the door and the ends to look for the problem.

Kino · Oct 23, 2018

If your light leak is on the bottom of the properly oriented image, then the leak (if there is one) would be on the top of the camera . The image is formed on the focal plane upside down and backwards...

shutterfinger · Oct 23, 2018

+1 for post 15.
When you load a developing reel frame 1 of the roll is nearer the center of the reel than the outside unless you unroll the film and start with the end connected to the spool.
Developing tanks develop light leaks around the center column the most.
Developing rolls without leaks then some with seems to rule out the tank/reels but I would inspect them carefully for cracks.

If you have ever looked at the ground glass of a view camera or if you put a ground glass on the film rails of your camera with the shutter open you will see that the top of the subject is at the bottom of the frame with the right side of the subject on the left of the ground glass and the left of the subject on the right of the frame with the bottom of the subject on the top of the frame.

Check the camera back for warpage, the hinge for bends, and the latch for secure connection when the back is closed (press in on the latch side at the bottom with your thumb and observe the top for movement).

fotoobscura · Oct 24, 2018

Good point/fact.

Camera looks fine to me- In fact the whole thing looks mint in my eyes. I think I'm going to swap out all the development gear I used for these last rolls and shoot another test roll to at least determine finally if it's the camera or the development.

Thanks

shutterfinger said:
+1 for post 15.
When you load a developing reel frame 1 of the roll is nearer the center of the reel than the outside unless you unroll the film and start with the end connected to the spool.
Developing tanks develop light leaks around the center column the most.
Developing rolls without leaks then some with seems to rule out the tank/reels but I would inspect them carefully for cracks.

If you have ever looked at the ground glass of a view camera or if you put a ground glass on the film rails of your camera with the shutter open you will see that the top of the subject is at the bottom of the frame with the right side of the subject on the left of the ground glass and the left of the subject on the right of the frame with the bottom of the subject on the top of the frame.

Check the camera back for warpage, the hinge for bends, and the latch for secure connection when the back is closed (press in on the latch side at the bottom with your thumb and observe the top for movement).

Sirius Glass · Oct 24, 2018

fotoobscura said:
Good point/fact.

Camera looks fine to me- In fact the whole thing looks mint in my eyes. I think I'm going to swap out all the development gear I used for these last rolls and shoot another test roll to at least determine finally if it's the camera or the development.

Thanks

And keep the center post in the tank.

fotoobscura · Nov 9, 2018

Wanted to follow up on this thread. (Pretty sure) it turned out to be the tank, the tank post, or ghosts in the machine- definitely not the camera. It was a pretty old two reel 35/120 tank but didn't show any signs of aging really. I shot about 7 'test' rolls using various tanks and I could find no fogging at all on any of the rolls- also didn't matter what film speed or any other minor details. I occasionally don't use the center post just out of laziness and so it's pretty much the only factor that may have been causing (occasional) fogging. Just to be safe I bought a new tank and will shelf the old one for testing/fun (solarized E6, anyone?).

TLDR; It was probably not using the center post that caused the issue.

Thanks for all the advice, thoughts, etc.

CMoore · Nov 11, 2018

If i might ask a beginner question.....assuming a camera is in "normal;" condition, it has not been dropped or anything...it has simply just aged.
Do light leaks always come from the Door/Back area.?
Is the foam around the mirror box just for noise, or is that a light-tight concern also.?
Thank You

shutterfinger · Nov 11, 2018

CMoore said:
Is the foam around the mirror box just for noise, or is that a light-tight concern also.?

Yes. Without a seal around the pentaprism light from the eyepiece can easily leak into the image path when the mirror is up.

Mysterious F100 light leak.

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