I purchased this lens a couple weeks ago. I seem to be having trouble locking in the correct auto focus for my 2 1/2 yr old son. At times the camera will think it has the focus locked in but he will be out of focus and the background in focus. I notice this most when the lighting is at all tricky. Like a backlit or dark lighting situation. It also seems to hunt a bit to find a lock. More so than the kit lens. Is this a bad copy that I should get replaced or normal for this lens?
Edit: I should point out that I put a Marumi uv filter and a hood on it. Could those be effecting autofocus?
Thanks
Last edited by sun_shard; 04-12-2012 at 07:38 AM.