Wat is het probleem?

‘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.’

Maar voor een oplossing moet je wel eerst uw toestel registreren.

‘This information is for residents of the United States and Puerto Rico only. If you do not reside in the USA or Puerto Rico, please contact the Canon Customer Support Center in your region.

Please register the EOS 5D Mark III. By registering, we will be able to notify you via email when service updates are available. If you already registered, please ensure you are opted-in to receive the notification.

http://www.usa.canon.com/cusa/support/consumer?pageKeyCode=prdAdvDetail&docId=0901e02480538fc7