In article <19970728165901.MAA21186@ladder02.news.aol.com>, bobzeller@aol.com says...

>I am considering buying a 500mm mirror lens. Any ideas out there? I
>heard that the one from Cambron at $299.00 got good reviews a few years
>back from Mr. Keppler in one of the photo magazines. But, I also hear
>that the Cambron quality if very poor. Also, how about the 600/f8 from
>Sigma. Does anyone have any experiences with that?

You don't say for what mount... If Nikon, the choice is easy: a (used)
older-version non-macro 500mm f8 Nikkor mirror (excellent, much better
than the off-brand versions, and usually about $250-350 in nice shape...).
If Minolta, my guess is that their 500mm mirror is pretty good (their
250mm f5.6 was...), and maybe a good deal at the used price.
Hope This Helps
(David Ruether - http://www.fcinet.com/ruether )