In article <3382974C.6125@metronet.com>, greylensman@metronet.com says...

>Does anyone have an opinion on the Tamron 500mm mirror lens?

Better than most mirrors, but if you use Nikon, the older-style
(larger, non-macro) Nikkor 500mm f8 is very noticeably better
(good enough to be still good on the TC14/14B converter!). The
Nikkor is sharp and contrasty enough to do full-bleed 8.5"x11"
crisp-looking magazine covers...
"Hope This Helps", "Bob Neuman", David Ruether
http://www.fcinet.com/ruether