Rainer T , Mar 03, 2007; 03:30 a.m.
Quantaray lenses are relabeled lenses from other manufactuerers (mainly Sigma iirc). In your case, the lens is not compatible with digital EOS cameras, and eventually it's not compatible with the latest film EOS that came out as well.
The problem is usually an errormessage as soon as you want to stop down ... when you use the DOF button, or when you press the shutter button.
Sigma did rechip some of their lenses (the newer lenses have loadable firmware). Depending on the lens, Sigma might (or might not) be able to rechip the lens.