GMCPhotographics wrote in post #10795613
The mft's are computer simulations and theoretical. They don't take into account any potential production or manufacturing tollerences. But the recent Canon lenses have been substantially superior optically. There's pleny of people ditching thier 300mm f4 IS L's after they upgraded their 70-200/f2.8 IS L lenses to the MK II version. It's THAT good and it's effectively free if you sell your old 300L and 70-200/2.8 IS L. Just add a 1.4 II tc but you get the extra IS ability and the reduced MFD. I think it's something that we'll see more of. The lenses are more expensive, but we'll need less of them. I can see that a 300/2.8IIL is now far more veratile than the old one. It makes a sharp 300/2.8, 400/4 and 600/5.6.
This is exactly what I've been thinking. I've always wanted the 500 f/4 for wildlife, but the new 300 could be a much more versatile lens if it lives up to its hype. Plus, it would cost about the same as the current 500. I'm sure the new 500 will be awesome, but very expensive.