5D MKIII light leak.....Just how serious of a problem isit??

[Rocco]

If Canon is offering to fix the problem I would guess they think it does effect the ability to get an accurate and consistent metering for exposure, and they feel it may be nessesary to fix it in order to reduce variablity in some instances.

It may be that from a PR perspective, it's simply worth every penny to offer their customers peace of mind. It is a lot of money to spend on a camera to have a problem like that. One that's vague in it's actual impact. And you're right, I don't think anyone has had the brass to test and see if the issue affects weather sealing.. (anyone want to volunteer?) Though, I'm sure Canon R&D did weather sealing tests before settling on the final design. Maybe it was simply a manufacturing problem after the fact.

[Dr Croubie]

Has anyone tried this, not with a lens-cap or body-cap, but with ND filters? I was doing some shooting in bright sunlight yesterday, with an ND400 and f/ stop enough to get me a 30 second exposure at iso100 (to blur the water).
How about at uber-macro, like 5x mag with f/16 (which turns into f/80 or so)?
Or astro?

If there's enough light coming through to affect metering with the caps on, and doesn't influence much at f/2.8-5.6, there's got to be a point where there's enough to influence metering to shift by 1/3 or 2/3 stop.
Of course with the shooting I did yesterday, I was metering from live-view, and with macro I tend to either live-view or shoot-histogram-adjust. But if the metering is wrong, even through the viewfinder and only under some very specific conditions, I think it's fair enough that they should fix it...

[jrw]

I've been looking for more information about the root cause of the 'light leak' to try to find out if it is a seal or bleedthrough of the panel. Now I see that Canon, Canada and UK, have stopped shipping the 5D3.

Does anyone have solid information about what the cause of the issue is?

[aZhu]

Electrical Tape is Canon's official fix:

http://www.lensrentals.com/blog/2012/05/the-fix-is-in

[jrw]

Saw the fix for the light leak. Am glad that it is light bleeding and not sealing that is the culprit.

[jks_photo]

@ jrw question is would you send your mkiii for the "fix"??

[Keith B]

I'm not surprised by "the fix." I figured it would be small piece of foam if it compromised sealing or tape if it was just light.
I'll send mine in a week before I sell it. It has no bearing on me or my shots.

[jrw]

@jks_photo I really doubt it. I have done a lot of testing on my body since this issue came to light and am not finding any real effect on the exposure metering. One night I sat in a room with the blinds drawn, the lights off, opened the closet door, and took shots of its interior. The only time I saw any variation was when I got up above ISO 12800 when the time went from alternating between 20 & 25 seconds to holding constant at 20 with the panel light on. Going by the serial number mine is a suspect, but I don't seem to have a body that is showing the degree of symptoms that others are. If it was I'd be thinking it over a bit more. I would probably be wondering if the camera would come back even better than when it left.