OK, so I've had my camera for a while, haven't used it as much as I'd like but am finally getting a chance to more. AND, I also picked up the 75-300 zoom this week - just got here today. Too late to go out and use it, but was just playing with it in the house and I noticed something. Have the camera in single AF mode - but when I point the lens and different objects the camera automatically focuses the image without me even partially depressing the shutter release - so it's acting more like continuous AF it seems. Is this normal behavior that I just didn't really notice with the 12-50 kit lens? I did pop the kit lens back on and sure enough it does the same thing, so I'm thinking it's normal. With the kit lens I was at the wide end of the zoom a lot and this behavior is not as noticeable there. Can't wait for tomorrow to get outside and use this new lens!