Hi guys, I cant find anything recent so, I've recently upgraded from the 50d to the 7d2. Everything going great with both my lenses, Canon 17-55 IS and the Sigma 70-200 OS. Couple of nights ago I had the 17-55 on and did some video, it was in low light and it kept ticking like it was focusing but it just wouldnt stop. So I turned it off. The next day taking some photos and I get the error 01 message, not sure if it was a coincidence or not. I've tried every fix I can find on the net but it hasnt changed. I put it back on the 50d and works like a charm. I've noticed at 17 and 20 its fine its when it gets into 28 and above it fails. Is the 7d2 just more sensitive, has anyone else had this problem and was it fixable

Chris