Hello all, I recently purchased a 30D (first digital, woo hoo!) with Sigma 70-200 f2.8 and Canon 17-55 f 2.8. I've noticed that even when the lenses are set to AF, the focus ring(s) can be moved, and indeed, sometimes i forget and adjust focus manually. Is it supposed to be this way? Does it harm the focus motor or any other mechanism in the lens to do this? Why doesn't it lock when in AF, like on my Minolta lenses? Thanks a bunch.