Pentax Spotmatic Light Leak

My Pentax Spotmatic which has been serviced in the last 5-6 years has developed a light leak. I would like to know what you think. It was on 7 frames this last roll. And it appears to be related to the shutter releasing as the leak is on solo frames with some bleed to the next frame. The horizontal band seem crazy as this camera has a vertical shutter. Thanks you in advance.

 

Is it lens flare? Do you use a lens hood?

Yes, I use a Lens hood on all my lenses, but some if not all of these 7 photos were taken with a Mamiya Sekor 135 lens for a Spotmatic II or a Spotmatic SP. I hope that isn't the problem.

The Spotmatic has a horizontally running shutter. The part of the picture showing "flare" is the lower part, seen from the camera's point of view. There isn't anything inside the camera, if you remove the lens, and hold the shutter open on "B", which could be reflecting light onto the film?

I'm still fishing around for this leak, I tending toward a leak in the meter switch or in the flash connection.

Not seen anything similar myself, but as it is fairly uniform across the single frame you have posted, is it possibly an issue with the actual lens itself ? Have you tried this lens on a digital body for comparison ?

I did try this, and some were funky but not the same. I tried the flash gun approach to the flash connector and the meter switch (on) and didn't see anything. I can't remember how many shots I took with the Mamiya Sekor 135 (for Spotmatic II-SP-F) but that is the best choice so far. I use this camera often and have never had this problem and the Mamiya Sekor is fairly new (a gift). Thanks for this input.

This may be the result of a "hesitating" mirror. The mirror is supposed to be all up before the shutter opened, but sometimes, the mirror was just half-way up, making half of the frame dark.

John, thanks for that input, I'll try watching the mirror to see if I can visually see hesitation.

Update: I just developed a roll and no leaks. I covered the PC flash ports with foil and tape for this latest roll. I should have removed it for a couple of frames but didn't so I assume that is the problem. I exposed some frames on the 'bad' roll using my flash and these were unaffected with leaks so that is why I tried this.

Update #2: still a slight problem will keep looking.

I still go with the guess that "the mirror is not all the way up when the shutter opens". because the old mechanism may likely to do that. I don't think the PC hole give any light to the mirror box, but the flash exposure is very fast. That is why the exposure is good.

You may be right, I'm going to retire the Spotmatic until I figure out what is EXACTLY the problem.

I'll close this off now, I found the leak source. There must be a baffle inside the body of the camera that has moved. The light is entering through the flash PC ports and the meter switch.

It looks like the leak comes from emulsion side, thus from the front. Check the foam light seal on the bottom edge of the front plate located below lens mount. Also check aroumd viewfinder. Maybe light leak is making its way from around viewfinder down through speed selection mechanism?