The final test I did with the 5D Mark III was take the lens cap off and meter off a relatively neutral wall. I turned on the backlight and nothing changed. I then pressed a 130 lumen flashlight up against the top LCD and the exposure didn’t change. I also ran the flashlight around the camera body and absolutely nothing changed.
So why do things change with the caps on?
I have no idea, none, ziltch!
So is this an issue?
On the body I tested, it doesn’t appear to be. If the camera acts properly with the lens cap off, who cares how it acts with the caps on? So please don’t return your 5D Mark IIIs, or cancel preorders or overreact. This “issue” may have a simple explanation.
However, if Canon says something is wrong, I apologize…… it just doesn’t appear there is an issue to me.