My d50 recently started acting up. My wife was using the camera and described seeing a very slow-moving (say 1/4 to 1/2 of a second) opening and closing of the image through the viewfinder when taking a picture earlier this week. I also noticed that the image through the viewfinder disappeared when taking a picture, then sort of slowly shifted back up into place. It doesn't happen all the time, maybe every 10-20 clicks, so we don't have a real strong sense of what we are even seeing, but something is definitely awry. I haven't had a chance to import the photos yet, but they look fine on the LCD. At worst they are a little blurry. I'm assuming this is some sort of problem with the mirror or shutter actuation mechanics, but I don't know much about the internal functioning of the d50 or if this would be a common problem. Any ideas on what it could be? Anything I can do to test? The camera is just under 2 years old, and has approx. 10k actuations. I was using it with a nikkor 18-200 VR and SB-600 when these problems arose. Any input is greatly appreciated.