I just purchased a Nikon 80-200mm f2.8 lens for $550. When I receieved the lens, look like the lens may have more than a couple of dustw inside the front of the lens. Does it worth $550? For doing what I'm doing (using it with a 35mm adatper), would this lens work? Or should I just return this lens because of dust inside the lens? Any suggestion is much appreciated.