You might remember my post about the focus problem I was having with my D600 (http://www.photo.net/nikon-camera-forum/00boQk). At the time I didn't know if it was my camera or lens that was causing the problem. However, I did confirm it was the camera and sent it back to Nikon where they had to do quite a few adjustments and repairs. I received the camera back from Nikon Repair this week and immediately noticed some kind of dust and/or residue on the corners while I am looking through the viewfinder. I did not have this problem before sending it off to repair and obviously if I did, they would have corrected it as on my repair ticket it shows they performed a general check and clean on my camera. It isn't very noticeable (if at all) on my images as I view them on my computer, but it is extremely noticeable looking through the viewfinder and it is distracting. I have emailed Nikon and they asked for me to upload a few images so they can see the dust spots. I know it is probable they will come back and say they do not see a problem, but I honestly feel very disappointed that this was overlooked and my camera was sent to me this way. Any suggestions on what the problem could be and how I go about dealing with Nikon? My sample images don't show the problem, but I feel as though something is wrong. Thank you in advance for your help.