Summary: Why buy a great lens and put a cheap filter over it? The lens is only as good as the weakest link. Have a great lens? Put a good, quality filter over it. A UV filter is a good investment not only to cut down haze but as a protection from damage. Shortly after buying a new Nikon D300 with the 18-200VR lens, my wife happened to be hiking in the mountains with it, slipped and rolled down a hill. The UV filter scratched, but protected my lens. A good investment.
Summary: I reseached a lot before buying this and am very pleased with my choice. It's thin, no vignetting, and does not affect the photographs in any way I can see. Why spend a lot on a lens and then put a rubbish filter on the front!!! Buy this one.
Summary: What can be said about a filter - not a lot unless it degrades the image or is of poor build quality. Well with this filter it is well made and does not degrade the image when on the front of a lens. I would recommend this filter.