Quote Originally Posted by Alan W View Post
That's exactly how you change the aperture on the older lenses,it must be stuck.
Agreed. The little arrow should move freely along the scale.
Try removing the lenses, if you are not sure how to do this just ask. Set the shutter to B and hold open, you should be able to see the aperture diaphragm. Moving the pointer as above should alter the aperture size. Should need no force to do this and if it won't move there is a problem.