Can anyone tell me about Varionar lenses for Nikon mount? I just come upon a Varionar Auto MC 28mm f2.8 for Nikon mount and I know nothing about it and can't find any info (which I'm guessing is probably saying a lot in itself). Just wondering if this is a paper weight or if it might actually be a good lens. If you have any experience with these or knowledge of them please let me know. Thanks!