Delivery of the Canon 1.4X III HAS STARTED

[kubelik]

Comparing 400mm f/5.6 achieved with the 100-400 vs. the 70-200 II + 2x III, Bryan's charts show that the native 400mm is a bit better all across the frame than the shorter zoom with the new extender.

I'd definitely be interested in some real-world impressions.

I remember someone a while back mentioning that this combination should be as good as the 100-400 at 400 f/5.6, and I remember both of us saying that was very, very, unlikely, almost impossible. I must say I stand largely corrected; it's not exactly the same but it's really darn close.

even more interesting is this: wide open, if you look at the ISO charts, the 70-200 II with the new 2x is actually better than the 200 f/2 + 2x III wide open. however, at 400 and f/ 5.6, the 200 prime kills the 70-200

 

[neuroanatomist]

I remember someone a while back mentioning that this combination should be as good as the 100-400 at 400 f/5.6, and I remember both of us saying that was very, very, unlikely, almost impossible. I must say I stand largely corrected; it's not exactly the same but it's really darn close.

To me, it looks like the difference between the 100-400 @ 400/5.6 and the 70-200 II at 400/5.6 is approximately equivalent to the difference between the 2x II vs. 2x III on the 70-200 II. It's not a huge difference, but it is noticeable. Probably enough that I wouldn't use the 70-200 II + 2x II, but I'd consider the combo with the 2x III if I didn't already have the 100-400mm.