My Sigma 70-300 is a tad short at the long end.
I've compensated with 500mm f8 mirror lenses (Lentar and Spiratone), but am thinking about faster primes combined with TCs.
I do NOT need a "birdie lens". I don't think I want to mess with something as long as a 600mm.
That leaves me with 300mm and 400mm primes from Pentax.
Just how impossible/heavy/awkward is the A 400mm f2.8? Will a Bogen 3221 tripod be adequate for it?
And how about the 300mm f2.8 lenses?
-Lon
