Sigma 600mm f/8.0 Mirror Lens Sample Photos and Specifications

[.timber>>code]

I have no first-hand experience with the lens in topic, but so far my 
experience with mirror lens is they are mostly soft. Of course there are 
differences, for example the f5.6/500 Rubinar is almost sharp (well 
let's say it's sharp as the Canon kit lenses :D) and f8/500 Phoenix is 
nowhere near to any kind of sharpness.

If you want to see a shot made with K10D and Sigma f8/600 then take a 
look at here:
http://somaa.fpn.hu/4257.pef

I think if it's for web ... it could be usefull, easy to carry solution 
for the budget. But if you need quality for larger prints ... forget it.

Sincerelly,
Timber