LX Light Leak Diagnosis?

chrodo7 · 01-11-2022, 01:28 PM

Hoping you all will be able to provide some thoughts as to what is causing this light leak. These all came from a roll of Lomo800 through my Pentax LX. The leak is in a consistent location and shows up on about 50% of the images in the roll. What’s surprising is that even with looking for it, there is absolutely 0 evidence of light leaks on the roll shot before, or the roll shot immediately after this one (both different film stocks). Is it possible it’s film stock specific? I’ve heard of light piping, but the fact that this shows up in the exact same spot, whenever it does show up, seems to point more towards an issue with the camera not the film. I appreciate any help here!

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Last edited by chrodo7; 01-11-2022 at 10:09 PM.

**gofour3** · 01-11-2022, 01:55 PM

Do the negatives also show the strip as well as your scans?

It's possible the film or development is the problem, if as you say this is the only roll of film having the issue.

Phil.

Not a Number · 01-11-2022, 01:56 PM - **1 Like**

Leaks like that are usually from the door hinge. You should replace all the light seals and probably the mirror bumper as well. I think the LX has some other bumpers in the mirror box but I don't think and of the kits include these.

chrodo7 · 01-11-2022, 01:56 PM

Originally posted by gofour3

Do the negatives also show the strip as well as your scans?

It's possible the film or development is the problem, if as you say this is the only roll of film having the issue.

Phil.

I have yet to go grab my film back from the lab (just got these scans back from them today). I'm guessing they do, but planning to go grab the film this evening to take a look.

---------- Post added 01-11-22 at 02:58 PM ----------

Originally posted by Not a Number

Leaks like that are usually from the door hinge. You should replace all the light seals and probably the mirror bumper as well. I think the LX has some other bumpers in the mirror box but I don't think and of the kits include these.

That's good to know. As far as replacing the seals, where do you source parts from? I've seen Jon Goodman's name mentioned quite a few times around here

**Viking42** · 01-11-2022, 03:47 PM

It does look like a door hinge seal problem. But it's odd that it's not on every frame, and not on the prior or subsequent rolls. Did you use a case or half-case on the camera body for some rolls/shots, but not on others? Something that would have covered the door hinge?

chrodo7 · 01-11-2022, 03:58 PM

Originally posted by Viking42

It does look like a door hinge seal problem. But it's odd that it's not on every frame, and not on the prior or subsequent rolls. Did you use a case or half-case on the camera body for some rolls/shots, but not on others? Something that would have covered the door hinge?

Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little.

Either way I'll probably replace the rear seals...even if it doesnt end up being the issue, it doesnt hurt

**Viking42** · 01-11-2022, 04:04 PM

Originally posted by chrodo7

Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little.

Either way I'll probably replace the rear seals...even if it doesnt end up being the issue, it doesnt hurt

Makes sense on how you hold the camera. Probably with big gloves or mitts on, given the winter weather

. Were the previous and subsequent rolls in cold weather as well? Perhaps the cold opened up a gap in the door hinge through contraction of the metal, that doesn't happen when it's warm? Kind of a long shot, but worth asking....

**ProfessorBuzz** · 01-11-2022, 05:18 PM

If you measure them and they recur every 38mm / 8 sprocket holes, probably the door hinge.

chrodo7 · 01-11-2022, 05:35 PM

Originally posted by Viking42

Makes sense on how you hold the camera. Probably with big gloves or mitts on, given the winter weather

. Were the previous and subsequent rolls in cold weather as well? Perhaps the cold opened up a gap in the door hinge through contraction of the metal, that doesn't happen when it's warm? Kind of a long shot, but worth asking....

Long shot indeed, but I actually thought the same thing! Perhaps the cold contracting the light seal a bit? But, unfortunately, all three were shot at least partially out in the cold (and, some of the light leak photos were inside where it was warm as well).

---------- Post added 01-11-22 at 06:41 PM ----------

Originally posted by ProfessorBuzz

If you measure them and they recur every 38mm / 8 sprocket holes, probably the door hinge.

Just took a look at the negatives and yep. While it’s not repeating on every shot, the shots where it does repeat it’s that spacing exactly.

When you say door hinge, are you meaning the side the door opens on (on the left by the film canister) or the side with the actual hinges (on the right by the take up spool?)

And is that (likely) solved by replacing the back light seals?

Thanks!

**Viking42** · 01-11-2022, 06:17 PM

Originally posted by chrodo7

Long shot indeed, but I actually thought the same thing! Perhaps the cold contracting the light seal a bit? But, unfortunately, all three were shot at least partially out in the cold (and, some of the light leak photos were inside where it was warm as well).

---------- Post added 01-11-22 at 06:41 PM ----------

Just took a look at the negatives and yep. While it’s not repeating on every shot, the shots where it does repeat it’s that spacing exactly.

When you say door hinge, are you meaning the side the door opens on (on the left by the film canister) or the side with the actual hinges (on the right by the take up spool?)

And is that (likely) solved by replacing the back light seals?

Thanks!

Well, I guess it’s not the cold then.

What the Professor means is the right side of the camera by the actual hinge. Not sure about the LX, but on my MX there’s a wider strip of foam on the door running right alongside the hinge. Mine turned gummy and disintegrated and needed replacing. It’s easy to do yourself if you want to buy the foam.

chrodo7 · 01-11-2022, 10:07 PM

To add to my confusion, there is a light leak AFTER the the last frame of the roll (see the photo of the end of the negative I just added to the post). Wouldn’t this mean the light leak has to be coming from the canister side of the back?

sfkazimierczak · 01-11-2022, 11:50 PM

Originally posted by chrodo7

Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little.

Hi. I know it might be a long shot as well, but did the camera went through some kind of security scanner? I had a similar problem on my ME Super. I have a scanner at work and didn't think it was that powerful, but as it turns out it is. I was confused what caused light leaks in my camera and then I realized they appear only on rolls I had with me in my office. Now I always remove my camera from my bag before security check and everything is ok. Well, was because my MES stopped working altogether but that's a different thing. Other than that it does look like a bad hinge seal.

**aslyfox** · 01-12-2022, 06:39 AM

Originally posted by chrodo7

. . . I appreciate any help here!

perhaps this might be of use:

https://learncamerarepair.com/downloads/pdf/pentax-lx-service-manual.pdf

and there is this thread

Quote:

Sources for information about the LX, please add your knowledge to this thread

Read more at: https://www.pentaxforums.com/forums/8-pentax-film-slr-discussion/419204-sour...#ixzz7HlPXQNTK

**ProfessorBuzz** · 01-12-2022, 06:57 AM - **1 Like**

Originally posted by chrodo7

To add to my confusion, there is a light leak AFTER the the last frame of the roll (see the photo of the end of the negative I just added to the post). Wouldn’t this mean the light leak has to be coming from the canister side of the back?

Not confusing at all. The film image frame is in the centre of the back of the camera. The light leak is to the left side of it, so somewhere on the canister side, so that can easily be the door seal.
An easy way to solve this: Put black electrical tape on the outside edges of the film back after loading a fresh roll. Take a few shots. Peel off one strip of tape (eg left side first). Then shoot a few. Then put it back, and peel off right side. Shoot a few more. Lather, rinse, repeat until you`ve gotten all the edges. Then yoù`d know for sure.
Plus, if one seal is bad, probably all of them are going to be bad, so it`s worth doing the lot of them.

---------- Post added 01-12-22 at 09:00 AM ----------

Originally posted by sfkazimierczak

Hi. I know it might be a long shot as well, but did the camera went through some kind of security scanner? I had a similar problem on my ME Super. I have a scanner at work and didn't think it was that powerful, but as it turns out it is. I was confused what caused light leaks in my camera and then I realized they appear only on rolls I had with me in my office. Now I always remove my camera from my bag before security check and everything is ok. Well, was because my MES stopped working altogether but that's a different thing. Other than that it does look like a bad hinge seal.

Any kind of x-ray source would damage the entire roll, not a thin strip at the left edge of a frame.

**Viking42** · 01-12-2022, 07:04 AM - **1 Like**

Originally posted by ProfessorBuzz

Not confusing at all. The film image frame is in the centre of the back of the camera. The light leak is to the left side of it, so somewhere on the canister side, so that can easily be the door seal.
An easy way to solve this: Put black electrical tape on the outside edges of the film back after loading a fresh roll. Take a few shots. Peel off one strip of tape (eg left side first). Then shoot a few. Then put it back, and peel off right side. Shoot a few more. Lather, rinse, repeat until you`ve gotten all the edges. Then yoù`d know for sure.
Plus, if one seal is bad, probably all of them are going to be bad, so it`s worth doing the lot of them.

+1. Excellent advice.

Chrodo, keep in mind that in the camera, the image is actually projected by the lens onto the film upside down and reversed. That makes sense if you look at film strip pic you added to your post.

01-11-2022, 05:35 PM	#9
chrodo7 Junior Member Join Date: Nov 2021 Posts: 36 Original Poster	Originally posted by Viking42 Makes sense on how you hold the camera. Probably with big gloves or mitts on, given the winter weather . Were the previous and subsequent rolls in cold weather as well? Perhaps the cold opened up a gap in the door hinge through contraction of the metal, that doesn't happen when it's warm? Kind of a long shot, but worth asking.... Long shot indeed, but I actually thought the same thing! Perhaps the cold contracting the light seal a bit? But, unfortunately, all three were shot at least partially out in the cold (and, some of the light leak photos were inside where it was warm as well). ---------- Post added 01-11-22 at 06:41 PM ---------- Originally posted by ProfessorBuzz If you measure them and they recur every 38mm / 8 sprocket holes, probably the door hinge. Just took a look at the negatives and yep. While it’s not repeating on every shot, the shots where it does repeat it’s that spacing exactly. When you say door hinge, are you meaning the side the door opens on (on the left by the film canister) or the side with the actual hinges (on the right by the take up spool?) And is that (likely) solved by replacing the back light seals? Thanks! Last edited by chrodo7; 01-11-2022 at 05:42 PM.

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01-11-2022, 01:55 PM	#2
gofour3 Site Supporter Join Date: Oct 2008 Location: Vancouver, Canada Posts: 8,093	Do the negatives also show the strip as well as your scans? It's possible the film or development is the problem, if as you say this is the only roll of film having the issue. Phil.

01-11-2022, 01:56 PM - 1 Like	#3
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Leaks like that are usually from the door hinge. You should replace all the light seals and probably the mirror bumper as well. I think the LX has some other bumpers in the mirror box but I don't think and of the kits include these.

01-11-2022, 01:56 PM	#4
chrodo7 Junior Member Join Date: Nov 2021 Posts: 36 Original Poster	Originally posted by gofour3 Do the negatives also show the strip as well as your scans? It's possible the film or development is the problem, if as you say this is the only roll of film having the issue. Phil. I have yet to go grab my film back from the lab (just got these scans back from them today). I'm guessing they do, but planning to go grab the film this evening to take a look. ---------- Post added 01-11-22 at 02:58 PM ---------- Originally posted by Not a Number Leaks like that are usually from the door hinge. You should replace all the light seals and probably the mirror bumper as well. I think the LX has some other bumpers in the mirror box but I don't think and of the kits include these. That's good to know. As far as replacing the seals, where do you source parts from? I've seen Jon Goodman's name mentioned quite a few times around here

01-11-2022, 03:47 PM	#5
Viking42 Site Supporter Join Date: Aug 2020 Location: Caledon, Ontario, Canada Photos: Albums Posts: 504	It does look like a door hinge seal problem. But it's odd that it's not on every frame, and not on the prior or subsequent rolls. Did you use a case or half-case on the camera body for some rolls/shots, but not on others? Something that would have covered the door hinge?

01-11-2022, 03:58 PM	#6
chrodo7 Junior Member Join Date: Nov 2021 Posts: 36 Original Poster	Originally posted by Viking42 It does look like a door hinge seal problem. But it's odd that it's not on every frame, and not on the prior or subsequent rolls. Did you use a case or half-case on the camera body for some rolls/shots, but not on others? Something that would have covered the door hinge? Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little. Either way I'll probably replace the rear seals...even if it doesnt end up being the issue, it doesnt hurt

01-11-2022, 04:04 PM	#7
Viking42 Site Supporter Join Date: Aug 2020 Location: Caledon, Ontario, Canada Photos: Albums Posts: 504	Originally posted by chrodo7 Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little. Either way I'll probably replace the rear seals...even if it doesnt end up being the issue, it doesnt hurt Makes sense on how you hold the camera. Probably with big gloves or mitts on, given the winter weather . Were the previous and subsequent rolls in cold weather as well? Perhaps the cold opened up a gap in the door hinge through contraction of the metal, that doesn't happen when it's warm? Kind of a long shot, but worth asking....

01-11-2022, 05:18 PM	#8
ProfessorBuzz Loyal Site Supporter Join Date: Feb 2018 Posts: 1,903	If you measure them and they recur every 38mm / 8 sprocket holes, probably the door hinge.

01-11-2022, 06:17 PM	#10
Viking42 Site Supporter Join Date: Aug 2020 Location: Caledon, Ontario, Canada Photos: Albums Posts: 504	Originally posted by chrodo7 Long shot indeed, but I actually thought the same thing! Perhaps the cold contracting the light seal a bit? But, unfortunately, all three were shot at least partially out in the cold (and, some of the light leak photos were inside where it was warm as well). ---------- Post added 01-11-22 at 06:41 PM ---------- Just took a look at the negatives and yep. While it’s not repeating on every shot, the shots where it does repeat it’s that spacing exactly. When you say door hinge, are you meaning the side the door opens on (on the left by the film canister) or the side with the actual hinges (on the right by the take up spool?) And is that (likely) solved by replacing the back light seals? Thanks! Well, I guess it’s not the cold then. What the Professor means is the right side of the camera by the actual hinge. Not sure about the LX, but on my MX there’s a wider strip of foam on the door running right alongside the hinge. Mine turned gummy and disintegrated and needed replacing. It’s easy to do yourself if you want to buy the foam.

01-11-2022, 10:07 PM	#11
chrodo7 Junior Member Join Date: Nov 2021 Posts: 36 Original Poster	To add to my confusion, there is a light leak AFTER the the last frame of the roll (see the photo of the end of the negative I just added to the post). Wouldn’t this mean the light leak has to be coming from the canister side of the back?

01-11-2022, 11:50 PM	#12
sfkazimierczak Forum Member Join Date: Nov 2014 Photos: Gallery Posts: 56	Originally posted by chrodo7 Nope, no case or anything. Within the roll I could explain it away by how I am grabbing the camera, or a minor light leak (within series of images shot in quick succession it seems to be better on later images). But the fact that it cropped up out of nowhere on just this roll is still making me scratch my head a little. Hi. I know it might be a long shot as well, but did the camera went through some kind of security scanner? I had a similar problem on my ME Super. I have a scanner at work and didn't think it was that powerful, but as it turns out it is. I was confused what caused light leaks in my camera and then I realized they appear only on rolls I had with me in my office. Now I always remove my camera from my bag before security check and everything is ok. Well, was because my MES stopped working altogether but that's a different thing. Other than that it does look like a bad hinge seal.

01-12-2022, 06:39 AM	#13
aslyfox Seeker of Knowledge Join Date: Aug 2016 Location: Topeka, Kansas Photos: Gallery \| Albums Posts: 24,583	Originally posted by chrodo7 . . . I appreciate any help here! perhaps this might be of use: https://learncamerarepair.com/downloads/pdf/pentax-lx-service-manual.pdf and there is this thread Quote: Sources for information about the LX, please add your knowledge to this thread Read more at: https://www.pentaxforums.com/forums/8-pentax-film-slr-discussion/419204-sour...#ixzz7HlPXQNTK

01-12-2022, 06:57 AM - 1 Like	#14
ProfessorBuzz Loyal Site Supporter Join Date: Feb 2018 Posts: 1,903	Originally posted by chrodo7 To add to my confusion, there is a light leak AFTER the the last frame of the roll (see the photo of the end of the negative I just added to the post). Wouldn’t this mean the light leak has to be coming from the canister side of the back? Not confusing at all. The film image frame is in the centre of the back of the camera. The light leak is to the left side of it, so somewhere on the canister side, so that can easily be the door seal. An easy way to solve this: Put black electrical tape on the outside edges of the film back after loading a fresh roll. Take a few shots. Peel off one strip of tape (eg left side first). Then shoot a few. Then put it back, and peel off right side. Shoot a few more. Lather, rinse, repeat until you`ve gotten all the edges. Then yoù`d know for sure. Plus, if one seal is bad, probably all of them are going to be bad, so it`s worth doing the lot of them. ---------- Post added 01-12-22 at 09:00 AM ---------- Originally posted by sfkazimierczak Hi. I know it might be a long shot as well, but did the camera went through some kind of security scanner? I had a similar problem on my ME Super. I have a scanner at work and didn't think it was that powerful, but as it turns out it is. I was confused what caused light leaks in my camera and then I realized they appear only on rolls I had with me in my office. Now I always remove my camera from my bag before security check and everything is ok. Well, was because my MES stopped working altogether but that's a different thing. Other than that it does look like a bad hinge seal. Any kind of x-ray source would damage the entire roll, not a thin strip at the left edge of a frame.

01-12-2022, 07:04 AM - 1 Like	#15
Viking42 Site Supporter Join Date: Aug 2020 Location: Caledon, Ontario, Canada Photos: Albums Posts: 504	Originally posted by ProfessorBuzz Not confusing at all. The film image frame is in the centre of the back of the camera. The light leak is to the left side of it, so somewhere on the canister side, so that can easily be the door seal. An easy way to solve this: Put black electrical tape on the outside edges of the film back after loading a fresh roll. Take a few shots. Peel off one strip of tape (eg left side first). Then shoot a few. Then put it back, and peel off right side. Shoot a few more. Lather, rinse, repeat until you`ve gotten all the edges. Then yoù`d know for sure. Plus, if one seal is bad, probably all of them are going to be bad, so it`s worth doing the lot of them. +1. Excellent advice. Chrodo, keep in mind that in the camera, the image is actually projected by the lens onto the film upside down and reversed. That makes sense if you look at film strip pic you added to your post.