5D Mark I problem

Discussion in 'Canon EOS' started by kiank, Jul 14, 2020.

  1. Noobie here, may be a stupid question but would really appreciate any input.

    I got a heck of a deal locally on a 5D mk i with a rokinon 14mm lens. It was untested and didn’t come with a charger. I bought a charger and when I finally powered the camera up, the viewfinder only displays a tiny circle, and it’s bordered in black. I can see the aperture open and close, but it won’t open fully. I’ve attached a photo.


  2. William Michael

    William Michael Moderator Staff Member

    I'd first investigate the theory that the lens is faulty: it looks like something is amiss inside the lens which is creating a physical vignette.

    Maybe the aperture is opening fully and what you see is something else blocking the inside the lens - can you post a couple of photos of the lens?

    Do you have another lens with which you can test the camera?

  3. Mark Keefer likes this.
  4. Thanks for your response! The only other lenses I can test are FD lenses with an adapter. I tried a 50mm f1.8 and still having the same problem. So I’m thinking it may be an issue with the camera. I’ve attached some photos




  5. Thanks for your reply. I did read this somewhere, but wanted to see what others thought. Is this issue something I could diagnose just by looking at it? I don’t see any obvious damage or anything out of place.

  6. William Michael

    William Michael Moderator Staff Member

    I agree. It looks like the camera has the problem. I guess that the 3rd and 4th photos are looking through the Rokinon 14/2.8 - if so on, then the face of it the lens looks fine.

    My guess is something is misplaced/misaligned in the 'mirror box assembly' - that's the issue JDMvW cited above. The usual fix is to replace the mirror box assembly.

  7. I wonder if the focusing screen has been removed? Look into the lens mount, at the top above the mirror there should be a plastic screen etched with fine lines.
  8. Thanks for the help! Quite a bummer but considering what I paid for everything I can easily get my money back just selling for parts
  9. Looks normal to me

  10. I don't have a 5D to compare it with, but I don't think the screen is present in your camera. You are surely seeing the base of the prism.
  11. Something doesn’t look right. You shouldn’t see the brass coloured part. This is what it should look like. It looks to me like the focus screen is missing.

    William Michael and John Seaman like this.
  12. You need a 5D screen
  13. Hope Robin is right, that is a pretty easy thing. VIDEO LINK
    They run around $35.

    Hopefully there is no mirror issue, but even a mirror is fixable.
  14. Suggest you reach out to a friend with a Canon or go to a camera store or pawn shop and see if the problem persists when you mount an EF lens. Check YouTube 5D Focus Screen Replacement to see if it is missing in your camera.
    You can check with Canon if the mirror arm upgrade has been done on your camera. It was done free of charge due to a manufacturer's defect, although that was a long time ago. You never know,,,. At the same time they can check the shutter count and do a cleaning. The 5D (original referred to as Mark 1) sensor frequently requires cleaning. Do not try to clean the mirror and sensor yourself.
    If your focus screen is missing I may be able to help, I may have a original Canon 5D Mark 1 focus screen from the time I upgraded my focus screen. For the cost of shipping and handling you may be in luck. If you are interested provide your contact details. I will have time next weekend to look for it. It is fairly straightforward to replace the focus screen yourself. Remember clean dust free surfaces when you take the lens off.

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