Actually, it's a short lens, since it's a f8 mirror, only a few inches long.
The camera in question's a Minolta Maxum 700si. I was using a 24-85 zoom on it, carrying a 70-210 with me. I was using an XD-11 in a housing with external strobe underwater.
See what I mean, we're already at $45. Thanks for the info, I'll hold onto this note, in case I get motivated. But I think it would be very priced to replace the electronics, so it might be better to go for a good digital...
I have a very limited digital camera, a little Sony. Ditto on the lottery but I hope I can get one that will take those lenses, one day.

http://www.rokkorfiles.com/500mm.htm