Not to far in the distant past while I was absent from this great place I was fortunate enough to be gifted with a new lens. At the time it was still wrapped in the paper and plastic and came complete with hood and bag.

The question is is what is the best use for this lens?
The lens in question is a

Sigma 600mm.jpg

Sigma Mirror Telephoto
f = 600mm
1:8.......whatever that means.
Macro 1:3 also stamped on it?

It has a filter mounted at the rear of the lens. So any advice would be much appreciated on what the best use for this lens would be, so perhaps I could go out and test it out.