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Thread: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

  1. #1

    Join Date
    Aug 2018
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    4

    DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    Hi LF Friends,

    i built this beautiful large format fix focus camera last week, and took the first photo on the left side wide open, the lens is a dagor type 130mm f12 wide angle. on this image i dont have any light leak.

    then i decided i need more in focus so i drilled a 3mm hole in a old creditcard and build that into the lens, its approximately f45 now.

    i took 6 different images today and all of them have lightleaks on same spot (right image), bottom left and right. please look at the camera and tell me, is it possible this is a reflection from the screws? or is the aperture the problem (not black)


    thank you very much for your help!

    ps. images are paper negative developed in reversal process. as soon as i have perfect results i will share the formula and process.


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  2. #2

    Join Date
    Aug 2018
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    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    Looks like your film holder is not sitting right, or you pushed it when removing dark slide.
    I like your camera and the pictures are nice!

    Sent fra min SM-G975F via Tapatalk

  3. #3

    Join Date
    Aug 2018
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    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    hi, i used 4 different film holders on photo session 1 and session 2, all the images shot wide open, session 1 dont have the light leak.

    i think it could be because at f45 coverage is greater and light is hitting the screw which is reflecting, what do you think?

  4. #4

    Join Date
    Aug 2018
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    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    here is the edge closeup Attachment 221727

  5. #5
    JoeV's Avatar
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    Oct 2006
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    Albuquerque, NM, USA
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    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    Quote Originally Posted by Draganb View Post
    here is the edge closeup Attachment 221727
    Looks like the fogging is coming from the side rails of the film gate. I noticed yours doesn't appear to have a groove across both sides that is supposed to match the light trap ridge on the holder. This may cause the holder to be susceptible to leaks, depending how it fits and the ambient light striking it.
    The photograph and the thing being photographed are not the same thing.

  6. #6
    Nicholas O. Lindan
    Join Date
    May 2006
    Location
    Cleveland, Ohio
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    302

    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    The problem could be the longer exposures at f45 - the darkslide was removed for a longer period of time and the light leak had a longer time to expose the film/paper.

    BTW - yes, the inside of the aperture hole should be painted flat black. Ideally the aperture should be as thin as possible, credit cards are pretty thick. If it were me I would get some brass shim stock from the hardware store and punch the hole.
    Darkroom Automation / Cleveland Engineering Design, LLC
    f-Stop Timers & Enlarging meters http://www.darkroomautomation.com/da-main.htm

  7. #7

    Join Date
    Nov 2017
    Posts
    506

    Re: DIY 5x7 fix focus LF Camera Light Leak / Reflection ?

    To be honest, I'm not sure at all it comes from those screws. But it is very easy to slap a bit of matte paint over those screws and wooden slats and see if that cures it.
    Expert in non-working solutions.

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