CHG_CANON wrote:
"Focusing Screen"?
Do you mean the mirror inside the camera body? Do you mean the viewfinder eyepiece on the back of the camera?
When I search focusing screen in the EOS 5DII manual, that tool is an electronic menu setting, not something physical. From your description it sounds like the mirror inside the camera, something I've never experienced, but a problem I think the original 5D had. If this is the problem, maybe your EOS 5DII is reaching end of life?
The mirror was still in place however as I said in my other comment I switched to my backup this was because I shoot live events and don't have the leisure to stop and tell the children that they have to wait to see Santa Claus because his camera is messing up.
I have to admit that I have been like others in the forum under the mistaken impression that your knowledge of Canon cameras went beyond just the users manual.
Thank you for enlightening us all.