[FarBox4697]

Hey guys!
So I recently got a Pentax 6x7 MLU and I’ve been having some issues with what appears to be a slight light leak going diagonally across the edge of the frame in some images. It only happens on maybe 3 out of 10 frames per roll and sometimes less. Sometimes when I’m holding the camera in portrait and some not, but always in the same spot on the negative.
I figure it isn’t coming from the back door because there are no light leaks outside of the frame on the negatives too. I just replaced the light seals around the ttl prism, but they still appear sometimes. I’m hoping someone else has had this issue and can give me some advice! Thanks for the help! I’ll post some images with the issue

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[leekil]

Is it the top right corner in the images? If so, I can see it in the first one, but not the second.

[JohnMc]

Look above the chimney on the right, most visible below the power line.


Would need to see more and the full uncropped frames, ideally as proper contact sheet(s). We don't know the time duration that a frame sits between spools or light conditions.

[Pghphotog]

Hey there!

Did you ever get this figured out? I have the exact same problem, except it's on the upper left side of the frame. The camera was serviced by Eric Hendrickson, who also seems baffled, and is unable to trace down the leak.

Thanks in advance for any help.

TK

[OrchidJulie]

Welcome to PentaxForums... I have deleted your other post as it was a duplicate of this one, and I'm moving this thread to the medium format sub-forum.

[Silent Street]

First thing to check is how careful you are to load and unload a 120 roll into the camera — light piping is what is visible here, as the leak is not replicated across frames. When loading the film, the ends (top and bottom spools) should be pressed down with your index and middle fingers as the leader is drawn out to the take-up spool, threaded and wound on slightly. Then place your hand over the loaded spool as you advance the leader to the START position. Close the back promptly.

Similarly when unloading the film, again protect and top and bottom spool edges as the last length of the leader is wound taut and secured with tape. Unlock the spool and use the tab seal to gently pull the spool out. Then wrap it is in tin foil ready for processing.

Many users do not understand how much more vulnerable 120 roll film is to light piping, a major cause of spoilage that is often mistaken for camera seals. Having said that, camera seals will need to be replaced, and it is a filthy, tedious, labour-intensive job. Aki-Asahi camera coverings in Japan make laser-cut replacement seals. I replaced the seal around the base of the TTL prism; there was no need to replace any other seals, and just as well too, as the TTL prism is a baptism of fire when it comes to getting rid of the worn seal!

[Pghphotog]

Ok. The leak is “replicated” on both frames above, and is also consistent on every frame on my camera, but usually only at shutter speeds of 125 and above, which would indicate a bright environment as those frames are being shot, and probably means there’s a light leak in the camera somewhere, and not a film handling issue.

---------- Post added 06-24-23 at 06:33 PM ----------

But where? The latch and all the seals were replaced by Erick Hendrickson in an attempt to address the issue, and i’ve taped up the door and the hinge with electrical tape, but i STILL get the consistent diagonal line in every frame. Is it somewhere in the prism? I have the metered one. Anyone with experience here, i would much appreciate your input.
Thanks.

TK

---------- Post added 06-24-23 at 06:34 PM ----------

But where? The latch and all the seals were replaced by Erick Hendrickson in an attempt to address the issue, and i’ve taped up the door and the hinge with electrical tape, but i STILL get the consistent diagonal line in the frames. Is it somewhere in the prism? I have the metered one. Anyone with experience here, i would much appreciate your input.
Thanks.

TK

[JohnMc]

Scans of film strips from a full roll including the edges are quite helpful. Did you tape off the prism?

[Pghphotog]

Not having much success pasting photos in here, but the leaks do extend past the frame, onto the edge of the film. Exactly like the top photo, only on the left side. I’ve taped off the door, and put some black yarn in the slight gap between the prism and the body. I guess for my next roll, i’ll tape off the prism completely, as well.

[Silent Street]

Not having much success pasting photos in here, but the leaks do extend past the frame, onto the edge of the film. Exactly like the top photo, only on the left side. I’ve taped off the door, and put some black yarn in the slight gap between the prism and the body. I guess for my next roll, i’ll tape off the prism completely, as well.

The Pentax 6x7 / 67 can either/both be actively used without any prism or finder attached; indeed, many people enjoy this somewhat primal but 'freestyle' method of direct-viewing of the image free from the limitations of either the TTL prism or chimney and waist-level finders. Taking off the TTL prism and running through a roll in active shooting might be a worthwhile experiment to exclude anything to do with the prism (or any finder) or prism fascia (on the body of the camera) and narrow down the suspect to the back cover area: possibly somewhere along the back there is a buckle or a crack along the top or bottom edges?

[Pghphotog]

Ok, thanks. So it’s probably not the finder.