Watch as I disassemble and attempt to clean the field lens on my Nikon E600 microscope.
UPDATE: dust speck ended up being on the relay lens directly below the camera f-mount. I thought I had rotated it earlier, but I guess I must not have. Problem solved!
UPDATE2: I discovered I can remove the top cover on the field lens with a tiny eyeglass repair kit screwdriver WITHOUT removing the turret and stage. Much easier.