I have set the aperture ring to A.
However your suggestion to Custom and mentioning Aperture made me look carefully at the custom settings. And voila - problem solved! Thanks ever so much!
In case anyone else has this problem, I went to Menu, then Custom, then page 4. The last item is 27: Using Aperture Ring. Select Enable.
---------- Post added 08-08-14 at 11:00 AM ----------
Originally posted by robthebloke Detach lens, reattach, and make sure it 'clicks'. I've had similar problems with fa lenses. They do work, but sometimes need a couple of attempts at attaching them. Could of course be that the focussing has broken for some reason?
I'd been able to attach the lens properly and I got a newer lens c.2009 to work. I did manage to follow another piece of advice - but thanks so much for your suggestion. I was getting desperate!