"The first thing you'll think when unpacking a newly-purchased lens and looking at the aperture ring is that it's screwed up. Not mounted on a camera, you only seem to be able to set about f/8 and smaller. This is normal: when you mount the lens on a camera it works perfectly, but since half the lens mount rotates as part of the bayonet mount, the part of the lens with the aperture index is rotated when the lens isn't on a camera. The aperture index mark moves, but you'll see that the diaphragm works perfectly, even when not on a camera. It's just the index mark which rotates when removed from a body."