Quote Originally Posted by HDNitehawk View Post
I noticed this to. The corners and mid frame are very much better on the 500mm II. It appears the corners and mid frame will be unusable on the 600mm by my standards. It will probably be 10 years before we see a 500mm III, and if Canon keeps heading the direction it is going there will be only full frame high end cameras, the corners and mid frame will really matter.
That's a good point, especially about full frame vs. crop. I live in 7D world and tend to think of these lenses as single subject wildlife lenses where the center is what matters most. But we're in the same boat here. 500II!!!!!