Originally posted by jon pafford Does anyone have the experience with these lenses? Is there a big different in size and weight? The 120-400 is 200 dollars cheaper. I have a 1.4 tamron that I could use on the 120-400 lens.
I believe the 120-400 is a fixed apature F5.6 lens, making it F8 with the 1.4 TC. I doubt AF would work with the TC attached
the 50-500 (BIGMA) has many posters in the forum, who have produced excellent shots with it.
I think both lenses have been reported as slightly soft, wide open at maximum focal length, although as I own neither this is only repeating (from memory) what others have posted.
check the lens review section