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  1. #1
    pixelrandy's Avatar
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    Strange Looking Frames - Mamiya 1000s

    Hello all,

    I hope you're having a great Friday. I noticed a few weeks back that I had four or so frames on a Portra 160 roll that a horizontal exposure line going across. It looks like a light leak, but it's very inconsistent. The battery was also low, as it died on the following roll. With a fresh battery in the body I did have a few additional frames out of six rolls (so not bad) with the same line. It's making me a little gun shy now and I'm leaning more heavily on my Pentax 67.

    Here are a few examples. The color shots were busts, so excuse the lousy scans. The B&W shot was taken with the fresh battery. The problem is more subtle, but you can still see it.

    Click image for larger version. 

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    Just about the same location on each frame. Sure looks like a double-exposure in that one spot, though I don't recall either the preceding or following frames having problems.

    I'd love to hear your theories!

    Thanks in advance,

    Randy
    Randy Wentzel
    Pentax 67
    Mamiya 645 1000S
    Various 35mm systems

    My Flickr

  2. #2

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    I would check for light leaks in the camera/film holder and pinhole in the shutter. Are your foam rubber seals deteriorating?

  3. #3
    Jaf-Photo's Avatar
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    I think that's a lazy shutter from weak batteries.

    Get a new silver oxide battery, for instance Energizer 544 , and you should be alright.

    (It never hurts to replace the light seals either but it most likely isn't the problem here).

  4. #4
    pixelrandy's Avatar
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    I should probably replace the seals. They're greasy and leave a grease mark if you tough them. Not sure what that's all about.

    I'll try the Energizer 544. I've been using Duracell PX28AB, which is a alkaline battery of course.

    Thanks! I'll report my findings in week or so. About to start processing my own film. I'll use a bright light on a long exposure to hunt down leaks before replacing seals. I'd like to find out for certain what's causing this.

    Randy
    Randy Wentzel
    Pentax 67
    Mamiya 645 1000S
    Various 35mm systems

    My Flickr

  5. #5

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    It's a light leak without a question. This camera relies on good seals for light tightness. Some cameras can be ok with bad seals, this one is not one of them. Replace the seals and you'll be fine. Pay special attention around bottom of the door and around the latch. With bad foam light leaks are almost guaranteed.

  6. #6
    DWThomas's Avatar
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    Drawing parallels with my Bronica gear, I would say that looks as though the seal at the opening end (opposite the hinge) of the back cover is degraded. There is a relatively sharp and straight demarcation across one part of the band, whereas the opposite edge is just a sort of fade. In such leaks, the light is hitting the film between the supply (or take-up) spool and the film gate; not in the masked film gate area. The resulting damage depends on the intensity of ambient light, the direction of the ambient light, and how quickly the film is wound between frames. That's the reason for the variations or apparent intermittent nature of the problem.

    I know the Bronica foam seals revert to goop after about 15 or 20 years, and since Mamiya is from the same country and time period, I suspect it could share a similar problem.

  7. #7
    Jaf-Photo's Avatar
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    My Mamiyas work fine with little or no light sealing at the back, but I got negatives that looked exactly like that when I ran alkaline batteries instead ox silver oxide.

    That said, it's never wrong to put in a fresh light seal along with the right batteries.

  8. #8
    mr rusty's Avatar
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    I agree. Its 100% a light leak. I have had identical leaks on my Mamiya 645. The light will be coming in around the catch. If you replace the seals make sure you get some foam underneath the back-lock pin - you can't stop it either side - voice of experience.

    The reason it only appears on some frames is because it depends on how the camera back is oriented and how long it is presented to the strong light source. When I refoamed my 645 the first roll was fine. The second roll, where I was carrying around the camera in sunlight had the light leak on most frames. If you look at the negs you will most likely see the light leak extending beyond the exposed frame area which proves it is a leak and not a shutter issue.


    I'll just add, when refoaming and using self-adhesive foam, wet the adhesive with a little water with some wetting agent or detergent in - not soaked, just enough to wet the surface. You can now slide the foam around into the correct position easily, and the glue will grab as soon as the water evaporates. This makes positioning mirror foams much easier as well!

  9. #9

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    With a bit of hesitation for fear of redundancy.
    Seals would be my bet, They degrade over time and leaving a residue is never a good thing.

    The seals should be absolutely dry,
    Heavily sedated for your protection.

  10. #10

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    Quote Originally Posted by mr rusty View Post
    If you look at the negs you will most likely see the light leak extending beyond the exposed frame area
    yep, check the negs for this, that will tell you if it's the back (light leak will show outside the image area)

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