#1. "RE: D5000 AutoFocus with Live View - Problem" In response to In response to 0
This is, unfortunately, as designed. If you use the optical viewfinder then the camera uses phase detection AF which is fast and accurate. When you use Live View the mirror has to be raised to expose the sensor so the camera can no longer use phase detection as the detectors are behind the mirror but has to use contrast detection for its AF. DPReview's comment on this was that it is so slow it's useless for most types of photography. This is how Live View works for most DSLRs except some of the later Sonys which have a secondary sensor for Live View so can keep the mirror lowered.