Originally posted by awscreo Is the aperture electronic on that lens? Are you able to control the aperture with the camera? If you can, then the lens should be mounted correctly, since it's aligned at the aperture control contacts.
It's all manual.
I put the lens on fast (ie I didn't 'line up the red dot). It looks like the lens set 1/4 turn counterclockwise from a normal lens. It almost comes loose (if the red dot on the lens is 180 degrees from the Pentaprism, but it is still catching. It rotates about 1/4th the way along the mount, the red dot will shift from the red dot on the camera Counterclockwise to the bottom of the mount, where it is loosest. Dumb move on my part. But it won't come off. I hope it doesn't need to go to Precision for a repair. I though maybe I could take the lens apart and try it that way?