I'm looking at a Pentax SMC Manual Stop Down 500mm F4 lens. If I purchase it I plan to use it on a 645n (with adapter)> Does anyone know what this lens is like? I would probably be shooting it wide open so performance at that aperture is important to me. What is the minimum focus distance. Can any one out there help...tks...jim

-- Jim Vanson (primary_colors@hotmail.com), March 26, 2000