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Does the EOS 5D Mark III have a light-leaking problem?

This is an issue that is heavily discusses in forums and on the web. People are reporting that their 5D Mark III’s are leaking light through the LCD panel on the top of the camera body. The leak seems to affect metering. There is a way to test if your body has the problem: put the cap on the body and cover the viewfinder, then put the cam in “P” mode at ISO 800 and turn on the LCD backlight. If the leak is present, the shutter speed will change after having turned on the backlight. Unfortunately there is more. The same issue seems to show up if a flashlight is firing on top of the LCD panel. And finally: there is also some people reporting that direct sunlight or strong light coming from top to down is also affecting the metering. I have two videos explaining the issue.

The test procedure summarized:

  • Remove lens and place the body cap on the camera
  • Apply the viewfinder cover on the viewfinder (to block any light from entering the camera)
  • Set ISO to 800 and camera mode to “P” (should set a shutter speed of approx. 10 sec)
  • Either turn on a flashlight near the top LCD panel or turn on the backlight for the top LCD panel
  • If light-leaking is present, the shutter speed will change to 5-8 seconds

Here the videos…

Light leaking from the LCD panel and changing metering:

Sunlight influencing metering:

There is also another video about the light-leaking issue, but it is in Chinese (and I do not understand it :-))


Happy Easter to all of you…

[via Fstoppers]
  • Edward

    Come on.

    NO ISSUE without the lenscap.
    Believe it or not I take pictures without the lenscap.

    • Frank

      Well, me too, usually. :-)
      But if this issue is real, it may influence your pictures.

  • Dan

    This all sounds silly to me. Put a lens on your camera and run some tests. Who cares what it does otherwise.

  • MS

    OK, no bodycap, no lens cap shooting seen is the third and they found this while time-laps shooting at night.

    You can see difference of the shots of 4″s and the 8″s maybe affect by headlight of cars.

    And if you don’t want get different result for same seen in variable situation – like cars, cigarette lighters, cellphones backlight or anything else LIGHTS can reach upper window you should wrap the camera by black cloths or somthing.

    Try it.

  • Chris K.

    I dunno, for a $3,500 camera it better damned well be perfect…If this is for real, sux and Canon should fix/refund.

    It could just be a software or metering logic electrical leak, not optical.

    Dumb question, what happens if you take a shot with the body cap on and the backlighting on? If it is a leak I’d expect it to show an uneven exposure.

  • I think Chris got the point. A $3500 cam shouldn’t have such issues. Even if it is true that in real life you wouldn’t probably ever notice it. But what if you are shooting in very low light, or take pics of the night sky? I wouldn’t want this to affect my pics. And it looks like it does influence the metering. Not good IMHO.

  • Heff

    The last video is in Korean, not Chinese.

    • Frank


  • We have performed a thorough test with a second EOS 5D MARK III body that proves the issue to be true: it should not affect daily usage of the camera but may be critical in night shots or astronomy shots. We wait for a fast free of charge solution form Canon.

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