Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,336   Posts: 1,537,568   Online: 1096
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1

    Join Date
    Apr 2005
    Location
    Oxford, England
    Shooter
    Medium Format
    Posts
    505
    Images
    35

    Light leak problem?

    Hi all,

    Recently I bought a Agfa Optima 1535 -- a short base rangefinder from the late 70s. It's a nice camera but I've been getting this odd light leak on every frame.

    There's a horizontal streak or pair of streaks running across the top of each frame, just a few mm down from the frame edge. The odd thing is that the door edges on this camera are quite a bit away from the film path. I just can't see how it'd be the doors leaking light that causes the problem. Also, this camera has a 'light-shield' that covers the film once it's exposed so it looks like the light leak is happening at exposure time or just before.

    Any suggestions? I include one frame to show the problem.
    Attached Thumbnails Attached Thumbnails lightleak_1.jpg  

  2. #2

    Join Date
    Jan 2006
    Shooter
    Multi Format
    Posts
    1,730
    It could be a light leak from a pinhole in the camera body that is being painted-on as you wind the film to the next frame. Do you see any "blobs" of exposure regularly spaced along the streaks?

    If not, it suggests either a manufacturing defect OR a pinhole in the camera back that is exposed to direct ambient light when you rewind the film (assuming 35mm cartridges) back to the cassette.

    What film are you using? What Gauge? Did you rewind in bright outdoor light? Did you turn the back of the camera up toward the sky as you rewound?

    You could try cutting a strip of photographic paper to fit the film path of your camera (marking what is up, left, right and down on the back of the paper), load that in total darkness, tie a string to the neck strap lugs, put the camera in direct sunlight and give it a gentle spin to rotate it around for a few minutes.

    Back in the darkroom, process the paper as normal and see if you can find a leak.

  3. #3
    tommy5c's Avatar
    Join Date
    Feb 2006
    Location
    Wyoming
    Shooter
    Large Format
    Posts
    161
    Images
    10
    It looks like a flare from the light in the top left. do you have more examples of the same.

  4. #4
    DBP
    DBP is offline

    Join Date
    Mar 2006
    Location
    Alexandria, VA
    Shooter
    Multi Format
    Posts
    1,883
    Images
    34
    Are the light seals on the door foam? Have they been replaced?

  5. #5
    TheFlyingCamera's Avatar
    Join Date
    May 2005
    Location
    Washington DC
    Shooter
    Large Format
    Posts
    8,325
    Blog Entries
    51
    Images
    438
    Looks to me like a leaky shutter curtain. Is this a vertical travel focal plane shutter? It could be that the shutter is not closing all the way, and allowing a gap to leak along the curtain edge.

  6. #6

    Join Date
    Mar 2005
    Location
    Southern California
    Shooter
    4x5 Format
    Posts
    659
    Of course in your sample frame, the horizontal line is vertical

    And it does look like like flare is affecting the left top portion of the frame.
    "A certain amount of contempt for the material employed to express an idea is indispensable to the purest realization of this idea." Man Ray

  7. #7

    Join Date
    Apr 2005
    Location
    Oxford, England
    Shooter
    Medium Format
    Posts
    505
    Images
    35
    The flare is just a deliberate thing in that shot (I was going for flare - it was sunset and I was facing almost directly into the sun) - I should have chosen a better example!

    The light leak is unrelated and is on every frame - including shots exposed indoors away from any potential source of flare. The problem has occured with 2 different films -- it's a 35mm camera -- and the second of those films was rewound and unloaded in subdued indoor light so it's unlikely to be that either.

    The doors of the camera have no foam seals -- the design is such that the edges of the door fit into narrow and deep grooves. Also, the edges of the door are a long way from the edge of the film - if it was a door leak I'd expect a more diffuse trace on the film.

    The leaky shutter curtain suggestion sounds like a good one -- I've been wracking my brains trying to work it out and that makies sense.

  8. #8

    Join Date
    Jan 2006
    Shooter
    Multi Format
    Posts
    1,730
    Quote Originally Posted by mcgrattan
    The leaky shutter curtain suggestion sounds like a good one -- I've been wracking my brains trying to work it out and that makies sense.
    Then there should be a start and stop to the streak on each frame; is there?

  9. #9
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,805
    Examine the surface of the film closely to see if there is a scratch where the print shows a line. If so, a good cleaning might cure the problem. It could also be a rough spot on the film gate or pressure plate.

  10. #10

    Join Date
    Jan 2006
    Shooter
    Multi Format
    Posts
    1,730
    Quote Originally Posted by Jim Jones
    Examine the surface of the film closely to see if there is a scratch where the print shows a line. If so, a good cleaning might cure the problem. It could also be a rough spot on the film gate or pressure plate.
    Ah, yes; pressure fog...

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin