So I just got a Nikon FM from KEH. There seems to be an issue with it, but im not sure if its me or the camera. Every lens I mount on it stops down when I change the aperture. I have the AI ring set properly, and the main lens im using on it is the Tokina 28-85 AT-X AI, but I took it to a camera shop over the weekend and tried an 85 1.4 and a 50mm 1.8 series E on it and it did the same thing, would stop down when I moved the aperture ring, even though the camera was set to auto indexing. Anyone familiar with this issue, is it the camera?