Canon USA issues a product advisory for the EOS 5D Mark III light leak issue:
Under almost all shooting conditions (including dark environments) this phenomenon will not affect your captured images. However, if you would like Canon to inspect your camera, we will provide this service free of charge upon request beginning in mid-May. Please contact Canon using the information below to request service.
Canon also released firmware updated v1.1.2 for the EOS 5D Mark III.
