As many of you know, LCD screens produce polarized light. As such, when you wear polarized sunglasses there is a certain angle where if you look at the screen, you will not be able to see anything. This is normal and expected.
On many Canon cameras the angle of view that causes issues is portrait orientation. On the 1D series cameras, it is a diagonal portrait orientation, which is an angle you are not too likely to be holding the camera at.
Well, on the 5D mark III it is the normal, horizontal angle you are most likely to be using!!!
Yes, that means if you are using polarized sunglasses and are holding the 5D mark III in your hand in the default orientation, YOU WILL BE UNABLE TO SEE THE REAR LCD SCREEN!
I am shocked that they did it this way, since they have gotten it right on every other camera I have tried.
Again, this is only an issue if you are wearing polarized sunglasses. But if you do routinely wear such sunglasses, it is a HUGE issue.
Otherwise I find the rear screen to be quite nice.