Will the 70-300 at 300 be any better than the 70-200 f/4+1.4x TC? The 70-300 is 1.05 kg, the 70-200 f/4 is 0.7 kg, and the 1.4x TCIII is 0.22 kg. According to the MTF charts at
http://www.usa.canon.com/cusa/consum...ef_lens_lineup
the lenses are similar (but the 70-200+1.4x TC is not shown). If one wants the ability to zoom from 70-300 without using the TC, then the 70-300 makes sense. If one has the 70-200 f/4 + 1.4x TC, it is not clear to me that it is worth the change. It would be good to see an AF speed performance specification. I find the 70-200 f/4 (with no TC) OK in AF speed, but not as fast AF as my 300 f/2.8.
Roger