The ever-inquisitive Roger Cicala at LensRentals has dismantled a light-leak-fixed Canon EOS 5D Mark III and compared it to an unmodified version. The solution, as proposed by every tool-shed tinkerer, appears to be a piece of black electrical tape, which Cicala says successfully stops stray light reaching the camera's metering sensor. When asked if he'd send his own Mark III back to be modified, Cicala points out that he doesn't 'do long exposure night photography with autometering.' But, in the unlikely event that you do, you can rest assured that Canon can fix your camera for you.

The 'light-leak' issue for the 5D III involved light from the camera's top-plate LCD illuminator reaching the metering sensor and skewing the results. The metering errors caused by this stray light only came when trying to photograph extremely low-light scenes (a situation in which it's unusual to use the camera's metering).