Jake's post makes me beg the ? is there that much difference between the D300 and the D200 regarding the AF button . I have a D200 and I put A5 on and with a nikkor 24-120 3.5-5.6 D lens find that I have to go to A6 in order to turn off the Shutter focus .Also I am not able to manual focus . Could it be the lens body combination ? C'mon Joseph K and Chris I notice thet you both have a D200 . I'm sure others are able to advise as well .