In article <19970222150301.KAA19681@ladder02.news.aol.com>, tfridmann@aol.com says...

>Need a little help, whick is the best 500MM Mirror lens to buy for a Nikon
>mount without going broke. I read they have AF mirror lens?? Are the
>major companies such as Sigma, Tamron, vivitar all about the quality??

The older-version (larger, non-macro) 500mm f8 Nikkor is the best
500mm mirror (well, the best mirror, period...) that I have seen. It
is also relatively low-priced, being easy to find (used only - and
I just happen to have a spare one to sell...;-). It is good enough to
produce fine images even when used on a converter (TC14/14B) - a rare
thing. The off-brand ones I have tried varied from barely adequate
to terrible. Even the Nikkor is hardly an optically perfect lens,
but it is good (roughly comparable in image quality [at f8 1/2 working
aperture...] to the big, fast, expensive ED lenses used wide-open).
I did not find a couple of samples of the newer compact Nikkor mirror
quite as sharp - and there is no AF Nikkor mirror.
Hope This Helps