Hey guys, just got a 35mm f/1.8 AF-S Nikkor lens in the mail. Was shooting around with it for a little and noticed it making a good amount of noise when auto-focusing. Is this normal? I thought I had read that the AF is quiet but maybe it isn't. It has a slight scratching sound to it like something being dragged over sand paper or something (but just very quickly while the lens is moving to get the shot in focus). Any help would be great from those who know this lens. Thanks.