I picked up a sigma 18-35 as part of a package with an Eos 5 I bought today. I get an err01 on my 50d if I fire a shot at anything other than wide open. I know the answer is probably no but is there anyway to fix this cheaply or myself. I've tried using the Depth of field preview button and giving the lens a shake/tap figuriing it might free them up but nothing.