Quote Originally Posted by Dr Croubie View Post
Anyway, so what I've found so far (in terms of what to look for on fleabay), with image circles above 600mm at infinity are...

Apo-Nikkors (above 360mm)...
Look again at those Apo-Nikkor data - you were most likely looking at numbers for 1:1, not infinity. Divide in half.

At the shorter end, the 355 G-Claron should just eke out 12x20 if you stop it way down. The 450 Nikkor M should comfortably cover 12x20, again stopped way down. With a bit of patience, either should be available in shutter for well under $1000. With a lot of patience, you might find the 355 G-Claron in barrel for a lot less.