and have a fat wallet or CC, this review is one of the best I have read for those using Nikon DSLR bodies.
Buy used
http://www.naturalart.ca/artist/fieldtests/500mmwars_sigma_nikon.html#500mm_wars_9
Birns and Sawyer 1000mm f: 4.5 Omnitar lens
Buy used
http://www.naturalart.ca/artist/fieldtests/500mmwars_sigma_nikon.html#500mm_wars_9
Birns and Sawyer 1000mm f: 4.5 Omnitar lens