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The 5D Mark III's Light Leak Issue Is Confirmed By Canon

Ruh-roh. The new Canon 5D Mark III might be a fantastic camera and a real champ in low-light situations, but a recently discovered hardware flaw could pose problems for photographers shooting in the dark.


It turns out that in extremely dark conditions the backlight on the 5D Mark III's top LCD display panel leaks light into the camera's body, reaching the AE sensor and throwing off the camera's auto-exposure settings. The problem has been demonstrated in numerous online videos, and as a result Canon has issued an official product advisory on its site.

In extremely dark environments, if the LCD panel illuminates, the displayed exposure value may change as a result of the AE sensor's detection of light from the LCD panel.


The issue shouldn't affect everyone who's dropped $3,500 on a 5D Mark III. It's negligible in well-lit conditions, and is really only a problem when the LCD display's backlight is turned on. But we're curious how Canon plans to resolve this problem since it's not something a simple firmware update can fix. [Canon via PetaPixel]

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Idunno, seems that it could be pretty easily fixed in firmware, either by disallowing the LCD backlight during AE as others have said, or -

The backlight, if this is a design defect and not a manufacturing defect - will pretty much spill a known amount of light onto the AE sensor in all cameras, and the AE sensor can simply be programmed to attenuate the signal in certain situations (low light, LCD backlight on).

Canon could also go the extra mile and include a utility that the user can invoke to measure the individual camera's LCD light leakage. One can simply put the body cap on (which would mean zero light for the AE sensor) and run it, then the AE sensor reports how much light it can see via the LCD backlight, then circuitry will attenuate that much light when the LCD backlight is on.

There are all sorts of ways to fix this in firmware, so it's not the end of the planet for you lucky MkIII owners.

Another solution, of course, would be to give yours to me, and I'll gladly deal with this horrible issue. :D