40D error message w/ WA lens when zoomed
I have a friend that has a 40D and the lens he was using is a Sigma wide angle zoom. I don't know which model but when he zooms wide he gets an error message that the lens and camera aren't communicating. Only happens on the full wide end of the lens. I suggested it may be the ribbon cable in the lens and it may have a break somewhere in it and when he zooms wide it causes the error message. Contacts are clean but that wouldn't matter since the problem only happens at one spot in the zoom. Any thoughts? Thanks.