I bought a second hand prime lens from a private individual yesterday... I tested the lens at his place and it seemed to work fine but I only took a couple of shots. This is a Nikon 300 f4 AF-S I am talking about. Today on my first real test with the lens, when i switched it on and tried to take the first shot, the AF-S squeeked and then stopped working. The lens does not auto focus at all, I can only use it in Manual mode When I got home, I can hear the autofocus is trying (a very very faint noise that its trying to do something). What a bummer, talk about a raw deal How much do you think a repair centre will charge to replace the AF-S motor (if thats the problem?) Damn, cant believe it!!!!!!!