See the top LCD panel on that gorgeous new Canon EOS 5D Mark III camera above? Early adopters say that light can leak through that spot and confuse the camera's Automatic Exposure (AE) sensor... and Canon isn't disagreeing with them. In fact, the company has admitted the issue today. "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," a Canon product advisory reads.
Before you consider returning your $3,500 investment, though, or canceling your pre-order, you should know that this won't be an issue for all shooters — only those that shoot in low light, and with that backlight turned on. In normal scenes, the amount of light produced by the backlight is negligible, according to early adopters. Still, considering how well the 5D Mark III performs in low light, we can see why Canon would want to move quickly to fix the issue. The company hasn't promised a fix quite yet, but says it's "now examining the countermeasures" and promises to post an update to its website once those countermeasures are arranged.
Cameratown did some extensive testing to root out the issue: see what it looks like in the video above, and at the source link below.