>>2575236I'll comment on the lenses I own:
All of which is referenced here, just scroll till you see the pertinent photos of things.. they appear in several clumps throughout this folder.
http://oh-hi.info/tech/I'll post seperately if you want me to point you at photos ive taken with each one.. but i have a shitload of photos and cbf determining what was what unless you really want... all are on the site listed here though between about 2010 and 2014
Tamron Adaptall-2 SP 500mm f/8 Mirror (55BB)
Very good. Dark to look through on a K5/K3, but then I used to use a high contrast screen with manul focus lenses, so that's additionally slightly darker than the stock screen.
ZM-6A 6.3/500 Mirror Zenit Tele Lens M42
Very good. As good or better than the 55BB
Caveats include they may have assembled the optics incorrectly and you need to do some trivial reordering of lenses. see the sketch in the above link.
Sigma 600mm f8 mirror
kind of shit, but mine has a common front mirror surface problem. (see link)
SMC Pentax Reflex 1:11 1000mm
very good
MTO-11CA 10/1000
very good, as good or better than the pentax
Sigma 600mm f8 Mirror-Telephoto Lens -Vintage (290698498273) minolta mount
not compared.
accidentally bough it to scavenge parts and it turned out to be a smaller diameter lens, very different in size to the other sigma i own
Tamron 350mm f5.6 (06B )
excellent. easily the best and most expensive catadioptric i own
>>2577232this is bullshit, and people need to stop saying it.
It is entirely dependant on the lenses you are comparing.
http://oh-hi.info/tech/telephoto_compare/ 