I just went out and bought a EF 50/1.8II thinking I'd have a fast prime to experiment with but it keeps giving error 99 on the 350D. When I first attached the lens it managed 3 shots @ 1.8, the minute I tried to close the aperture down and take another shot it spat error 99.
I've tried removing and replacing the CF, removing the lens and cleaning contacts on both it and the body, replaced battery with a freshly charged item. Removed lens again and tried the 18-55 which works error free.
'Apparently' the older lenses require more voltage or some jazz when closing down the aperture, causing failure and error 99. Does this sound correct?
I know it's a cheap lens but I was really looking forward to it 

