Finding a light leak

Discussion in 'Camera Building, Repairs & Modification' started by reub2000, May 30, 2006.

  1. reub2000

    reub2000 Member

    Messages:
    646
    Joined:
    May 23, 2006
    Location:
    Evanston, IL
    Shooter:
    35mm
    I have an Canon AE-1 with a light leak. It has caused light streaks of various colors (but mostly red) on film. The problem is that I don't know where the light leak is coming from. I've tried shining a flashlight through the lens, and then using a bulb exposure, but I can't find any light leaking anywhere. Is there a better way to find the source of the light leak?
     
  2. Ray Heath

    Ray Heath Member

    Messages:
    1,020
    Joined:
    Dec 29, 2005
    Location:
    Eastern, Aus
    Shooter:
    Multi Format
    g'day reub,
    in older cameras the problem is most likely the foam light seal around the film door

    i have several Canons of this vintage and model, AE1 & AE1P, they have all had this problem

    the foam degrads and falls offf leaving a sticky residue

    it can be replaced easily, either by the owner or a technician

    if doing it yourself, try using the felt from film cannisters
     
  3. resummerfield

    resummerfield Subscriber

    Messages:
    1,361
    Joined:
    Jan 28, 2005
    Location:
    Alaska
    Shooter:
    Multi Format
    Jon Goodman, an APUG member, sells an outstanding kit to refoam that camera. I have refoamed cameras before, and Jon's kit is by far the easiest to use. Contact him at "Jon_Goodman@yahoo.com"
     
  4. reub2000

    reub2000 Member

    Messages:
    646
    Joined:
    May 23, 2006
    Location:
    Evanston, IL
    Shooter:
    35mm
    One question, the foam where that the mirror rests on when it is up is worn away. There is a small gap between the mirror and the top. Could any light be leaking from the viewfinder onto the film?
     
  5. reellis67

    reellis67 Subscriber

    Messages:
    1,887
    Joined:
    Mar 10, 2005
    Location:
    Central Flor
    Shooter:
    4x5 Format
    Get one of Jon Goodman's kits. You will easily be able to replace all the light seals and the mirror bumper for next to nothing. I've done probably 8 cameras so far and never had a problem. Jon's kit comes with great instructions and he is a very easy person to deal with.

    - Randy
     
  6. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,942
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    The foam for the mirror and the foam light seals are the same material. It could be either, but the light seals in the back are more likely, unless you often photograph with your eye away from the viewfinder. It makes sense to have them both replaced at the same time.
     
  7. DBP

    DBP Member

    Messages:
    1,896
    Joined:
    Mar 22, 2006
    Location:
    Alexandria,
    Shooter:
    Multi Format
    Replacing all the foam is usually pretty easy, if sometimes a little messy. I've done it while watching TV. If you don't want to buy a kit, the adhesive backed craft foam sold in art stores works well, as does felt.
     
  8. reub2000

    reub2000 Member

    Messages:
    646
    Joined:
    May 23, 2006
    Location:
    Evanston, IL
    Shooter:
    35mm
    OK, I e-mailed Jon asking how much he wants for the kit. If I do replace the foam from the mirror, I might as well clean off the foam that has spread over the focusing screen. How might I acomplish that without scratching it?
     
  9. ricksplace

    ricksplace Member

    Messages:
    1,565
    Joined:
    Jan 22, 2006
    Location:
    Thunder Bay,
    Shooter:
    Multi Format
    I have to put in a plug for John Goodman's product too. I bought one of his bigger kits, and have replaced all the light seals on three 35mm slr's and a mamiya 120 film back. There's enough left in the kit to do several more cameras. He sent me instructions by email for a particular camera I needed to do. No extra charge for the extra instructions. Quick service and mail turnaround.
     
  10. reellis67

    reellis67 Subscriber

    Messages:
    1,887
    Joined:
    Mar 10, 2005
    Location:
    Central Flor
    Shooter:
    4x5 Format
    Be very careful doing this. I would recommend first using compressed air, then using a paint brush or moderate quality - i.e. one that is very soft. Do not use solvents on the focusing screen, or any liquid for that matter. Most of the debris should brush off with patience and time.

    - Randy
     
  11. reellis67

    reellis67 Subscriber

    Messages:
    1,887
    Joined:
    Mar 10, 2005
    Location:
    Central Flor
    Shooter:
    4x5 Format
    Also, be sure not to touch the mirror - it is top coated and will easily be damaged. Hold the camera so that debris falls out when you clean it. I usualy hold them upside down (lens mount facing the floor) to clear crumbly mirror bumpers.

    - Randy
     
  12. resummerfield

    resummerfield Subscriber

    Messages:
    1,361
    Joined:
    Jan 28, 2005
    Location:
    Alaska
    Shooter:
    Multi Format
    The focus screen is easily damaged. The old foam will be very sticky, so be careful brushing it, to avoid getting it onto the mirror. I would try GENTLY picking at the old foam with tweezers.
     
  13. reub2000

    reub2000 Member

    Messages:
    646
    Joined:
    May 23, 2006
    Location:
    Evanston, IL
    Shooter:
    35mm
    I'd be worried with compressed air that I'd accidentally get it in it's frozen liquid form. I have tried using a rocket blower in the past with no luck.
     
  14. Ray Heath

    Ray Heath Member

    Messages:
    1,020
    Joined:
    Dec 29, 2005
    Location:
    Eastern, Aus
    Shooter:
    Multi Format
    hey guys, i don't think you need to be that delicate, the mirror is not surface coated so it will not scratch easily

    try some metho or alcohol and cotton buds