Dust or crack on the sensor?
My dad has a Nikon D700 and about two years ago he accidentally dropped it. It fell on the lens and they got stuck. He took it to a repair shop and they were able to get it out, camera still working and all.
I noticed a small black dot on the upper right corner of some pics, I changed to different optics but it's still there. Depending on the aperture you can see the dot blurred or focused.
I tried many times the "clean image sensor" option in the camera but no change. I checked the mirrors but they seem ok, crack and dust free.
I'm almost sure its a crack on the sensor's glass... is there a way to replace it?