I've just noticed that there is a problem with the viewfinder in my 50D. It seems to have somewhat of a 'zoom burst' effect on the image as seen through the finder - see the photo below for my rendering of it! I've had the camera for a while now, and it's the first time it has behaved like this. The photos themselves are unaffected; the issue is just within the finder. The camera has never been dropped / abused in the slightest, so I'd be surprised if the prism had come loose or something, but it's a possibility...
Has anyone had a similar problem / know of a solution? It's not a fatal flaw as I can still use the camera reasonably well, but it is getting annoying...