[fabricis]

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Hi everyone,

this is my first post in the PentaxForums. So, go gentle is I miss any protocol
I’m having light-leaks with one of my two LXs. I was planning to do some tests but before I start burning film for nothing I decided to ask here for any advice.
As you can see from the attached contact sheet the leak doesn’t show all the time. But when it does it always shows the same pattern. Sometimes it is stronger and sometimes it is weaker though!
Any idea about what may be causing this problem?

Thanks!

If I take a good look at the pictures than I notice there are lighter stripes from top to bottom on 9636, 9640 and 9641. They are quite obvious here, so I get the idea that it is not the camera, but that the filmcartridge leaked. Sometimes you see on the right side a very heavy "leak" . But many pictures suffer this pattern you see in the pictures I mentioned. The stripes are small at the top and wide at the bottom and cover the whole picture from left to right.

[MikeMcE]

the whole negative will speak. looks like a foam seal issue,
Is the fog all the way edge to edge (through sprocket holes)?

look on the hinge pin side, is the light foam sticky.

With removable door, door can also "warp"

[MadBill]

It is hard to tell where a light leak is unless one does a controlled test. This is what I did with an old FED 2 that leaked badly. Toward the end of a test roll of film I covered the camera with a dark cloth and cranked through four exposures. This put unexposed film from the cassette to once around the take-up spool. I then left the camera sitting around in the light for a couple of days and also held the camera in various position in direct sun so all side would be exposed. I then covered the camera again, advanced the film one frame, exposed just the lens, and took a picture to mark the end of the test area. The developed film showed several specific locations where leaks were occurring.

[Alex645]

this is my first post in the PentaxForums.
I’m having light-leaks with one of my two LXs. I was planning to do some tests but before I start burning film for nothing I decided to ask here for any advice.

Welcome to the forum! Although the light leak could be coming from your camera, it could also be a light leak when the film was developed. #9640 shows the light leaks aligned with the sprocket holes, which is a typical sign that it happened during processing and not necessarily in camera.

Who developed the film?

[Not a Number]

From my experience the vertical streaks such as in xx43 and xx48 are caused by a leak on the hinge side near the take up reel. Leaks here can bleed through the sprocket holes to layers underneath. The amount of leakage and frames affected varies depending on the amount of the hinge area is exposed to.

A simple test is to put a small LED soldered to some very thin wire and put in the take reel compartment. Connect the LED and check for light leaks in a dark room or closet. If the wire is thin enough it should not cause leaks in itself. On the film canister side you can use a small keychain LED.

I used to use a small "grain-of-wheat" incandescent bulb (common with model railroad builders) to do this.

[stevebrot]

Welcome to the Pentax Forums!

As noted above, there are a number of possibilities. I will attempt a summary:

• Light leaks that extend beyond the frame boundaries:
  • Leaks into film chamber:
    • Film door grooves...primarily at negative edge, though may extend into frame
    • Hinge seals
  • Leaks occurring outside the camera
    • Film cassette felt...mimics hinge seal
    • Mishandling during processing
• Light leaks that only show within the frame:
  • A leak into the mirror box during exposure, including from the viewfinder/waist-level finder. May also occur due to bright light at the lens mount, e.g. electronic flash at close range.
  • A leak from the shutter itself

Steve

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Last edited by stevebrot; 11-02-2020 at 03:03 PM. Reason: added some stuff

[fabricis]

If I take a good look at the pictures than I notice there are lighter stripes from top to bottom on 9636, 9640 and 9641. They are quite obvious here, so I get the idea that it is not the camera, but that the filmcartridge leaked. Sometimes you see on the right side a very heavy "leak" . But many pictures suffer this pattern you see in the pictures I mentioned. The stripes are small at the top and wide at the bottom and cover the whole picture from left to right.

Cheers,

Thanks for your reply. I had also noticed those vertical strips you mention. But they are the result of the quick and dirty scanner I use for my contacts:

PICSCANNER

Here is a better scan of 9640:

[stevebrot]

Cheers,

Thanks for your reply. I had also noticed those vertical strips you mention. But they are the result of the quick and dirty scanner I use for my contacts:

PICSCANNER

Here is a better scan of 9640:

I guess I forgot that one...scanner artifact.


Steve

[Alex645]

I had also noticed those vertical strips you mention. But they are the result of the quick and dirty scanner I use for my contacts:

So the repeating pattern light leak is worst in #9623 and then less pronounced but same location in other frames?

Are there any missing parts to the exterior of your camera? If not, on your next roll, indoors in subdued light put some black camera tape (if opacity is unknown, use more than one layer) over all the camera back gaps right after loading the next roll.

Another possibility is that there are holes in your shutter curtain. In that case, you'd want to keep your lens cap on and something to block the light on the viewfinder window as much as possible.

[fabricis]

the whole negative will speak. looks like a foam seal issue,
Is the fog all the way edge to edge (through sprocket holes)?

look on the hinge pin side, is the light foam sticky.

With removable door, door can also "warp"

Thanks for your insights.

The leak is going all the way through the edges indeed. Here is a picture of the negative for 9648:



Regarding the sealing foams. When I compare the two LXs, I see the faulty one does show much more wear and tear along the door hinge. I found these on ebay but they are not shipped to Belgium... :-( I also found this other post about Jon Goodman, who also sells them. I'll try him directly.

As for the door. Since I have two of them and the other doesn't show the problem (using the same lens) I looked and compared them carefully and it seems the faulty one does show an ever slight bend. So, I'll look into that possibility too.

Thanks again!

---------- Post added 11-02-20 at 05:08 PM ----------

It is hard to tell where a light leak is unless one does a controlled test. This is what I did with an old FED 2 that leaked badly. Toward the end of a test roll of film I covered the camera with a dark cloth and cranked through four exposures. This put unexposed film from the cassette to once around the take-up spool. I then left the camera sitting around in the light for a couple of days and also held the camera in various position in direct sun so all side would be exposed. I then covered the camera again, advanced the film one frame, exposed just the lens, and took a picture to mark the end of the test area. The developed film showed several specific locations where leaks were occurring.

Thanks for the testing tips. I will surely consider them as I had no plan devised yet.

There is just one thing I don't understand. What do you mean by "exposed just the lens"? You uncovered just the lens after covering it again and advancing the film?

Thanks again!

---------- Post added 11-02-20 at 05:13 PM ----------

Welcome to the forum! Although the light leak could be coming from your camera, it could also be a light leak when the film was developed. #9640 shows the light leaks aligned with the sprocket holes, which is a typical sign that it happened during processing and not necessarily in camera.

Who developed the film?

Thanks for your reply!

The effects on #9640 have already been explained. They were scanning artefacts.
The development is not the source of the problem. I develop my own film and in the same tank I mixed films from both cameras and one shows the problem and the other not. I also usually use bulk film but the problem also shows when using pre-filled film.

---------- Post added 11-02-20 at 05:15 PM ----------

Welcome to the Pentax Forums!

As noted above, there are a number of possibilities. I will attempt a summary:

• Light leaks that extend beyond the frame boundaries:
  • Leaks into film chamber:
    • Film door grooves...primarily at negative edge, though may extend into frame
    • Hinge seals
  • Leaks occurring outside the camera
    • Film cassette felt...mimics hinge seal
    • Mishandling during processing
• Light leaks that only show within the frame:
  • A leak into the mirror box during exposure, including from the viewfinder/waist-level finder. May also occur due to bright light at the lens mount, e.g. electronic flash at close range.
  • A leak from the shutter itself

Steve

Thanks for the exhaustive list. At this point I'm leaning towards the hinge seals as the culprit.

---------- Post added 11-02-20 at 05:24 PM ----------

So the repeating pattern light leak is worst in #9623 and then less pronounced but same location in other frames?

Are there any missing parts to the exterior of your camera? If not, on your next roll, indoors in subdued light put some black camera tape (if opacity is unknown, use more than one layer) over all the camera back gaps right after loading the next roll.

Another possibility is that there are holes in your shutter curtain. In that case, you'd want to keep your lens cap on and something to block the light on the viewfinder window as much as possible.

Thanks for your reply.
No missing parts. The camera is complete. I have two and they are the same but the other works well.
Also, the leak extends beyond the frame limits which makes it difficult that the problem is linked to the curtain.
But I will do tests that will involve "blackening" the body as you suggested.
Thanks again!

[Not a Number]

You can always swap back covers since they are removable to use a data back. Then shoot a test roll in both cameras. Or shoot half a roll in on camera, rewind (leaving the leader),, put it in the other body and advance it forward (lens cap on) and finish the roll. If the leak swaps bodies with the back cover you have your answer.

[MikeMcE]

After seeing the roll, look a few frames on both sides of that one . If your hinge seal is the culprit, your negatives rolled around the spool, will show the outline of other perforations , as the diameter is changing as the film is taken up, and the fog goes through all


Hang up and DRIVE!

[fiddlefye]

How much leakage there is will often depend on simple things like how long between frames and how you were holding the camera in between shots.

[MadBill]

Thanks for your insights.

The leak is going all the way through the edges indeed. Here is a picture of the negative for 9648:



Regarding the sealing foams. When I compare the two LXs, I see the faulty one does show much more wear and tear along the door hinge. I found these on ebay but they are not shipped to Belgium... :-( I also found this other post about Jon Goodman, who also sells them. I'll try him directly.

As for the door. Since I have two of them and the other doesn't show the problem (using the same lens) I looked and compared them carefully and it seems the faulty one does show an ever slight bend. So, I'll look into that possibility too.

Thanks again!

---------- Post added 11-02-20 at 05:08 PM ----------



Thanks for the testing tips. I will surely consider them as I had no plan devised yet.

There is just one thing I don't understand. What do you mean by "exposed just the lens"? You uncovered just the lens after covering it again and advancing the film?

Thanks again!

---------- Post added 11-02-20 at 05:13 PM ----------



Thanks for your reply!

The effects on #9640 have already been explained. They were scanning artefacts.
The development is not the source of the problem. I develop my own film and in the same tank I mixed films from both cameras and one shows the problem and the other not. I also usually use bulk film but the problem also shows when using pre-filled film.

---------- Post added 11-02-20 at 05:15 PM ----------



Thanks for the exhaustive list. At this point I'm leaning towards the hinge seals as the culprit.

---------- Post added 11-02-20 at 05:24 PM ----------



Thanks for your reply.
No missing parts. The camera is complete. I have two and they are the same but the other works well.
Also, the leak extends beyond the frame limits which makes it difficult that the problem is linked to the curtain.
But I will do tests that will involve "blackening" the body as you suggested.
Thanks again!

There is just one thing I don't understand. What do you mean by "exposed just the lens"? You uncovered just the lens after covering it again and advancing the film?

I wanted a picture after the test segment so I could be certain where it started and ended. I covered the body of the camera before advancing the film to prevent leaks after the film was advanced from confusing the result. With the lens uncovered I was able to take the picture to mark the end of the test section. You can hold the developed film up to the back of the camera to see where the leaks are occurring. Don't forget the image on the film is upside down.