Zenit Tair-11A is
very sharp lens.. However not easily found. And it suffers from coma somewhat at the corners (but virtually no CA, when stopped down to f/4).
Hhave a look at the shot of Proxima (crop, from 1/2 way to the corner of the frame, I will try to post the full frame later today) here:
http://www.iceinspace.com.au/forum/s...31&postcount=7
Canon 100mm F2.8 FD is also very good (but shorter... ).
I have both, they are excellent for wide shots