Having recently received this lens (new) I'm surprised at how noisy it is to focus. I was expecting something along the lines of the O45 or the P14 or any of the kit zooms. I've tried it on 3 cameras (2 Olympus and 1 Panasonic) and they are all the same. Have a got a bad one? Any input gratefully received. P.S. I'm not talking about the infamous rattlesnake, this is definitely the focus motor.