Alright, so I have Canon 5D that has an issue I've never heard of, nor can I find any information on. When I look through the viewfinder, I see only a circle of visible image, as if the picture were vignetted. This does not change when I change lenses, nor when I change settings or anything on my camera. I've asked several other professionals I know, but no one seems to know what could be wrong. Now, I will take it to a shop if necessary, but this is my main camera for work so I would rather not have to leave it somewhere to be worked on. Has anyone heard of this happening before or have any suggestions? Thanks.