Im looking for a good telephoto lens. The main things Im looking for are fast focusing and sharp focus. I have Nikon D-50. Cost is an issue So I would like to keep it as affordable as possible, are there any quality lenses in the 500-1000 range? I was looking at the 80-400mm f/4.5-5.6D ED AF VR Zoom-Nikkor lens, anyone know about this lens. Is the vibration reduction realy useful?