Now we see through a glass, darkly...
- Apr 5, 2016
My comparisons are with the 5D2, 6D2, and 7D2.
I find the 7D2 AF system beats the 5D2 in every way. I find that the 7D2 beats the 6D2, except in live view, where the 6D2 beats the 7D2.
I assume that any replacement to the 7D2 will put it back on top for both.
Any of the current three digit Rebels (Txi/xx0D) beat the AF of the 5D Mark II. It's the weakest thing about the 5DII.
The 5D Mark III has a 1D X level AF system that is noticeably better than the 7D Mark II, both in terms of accuracy and consistency from shot-to-shot.
The 6D Mark II has a PDAF system very close to the 80D PDAF system, but is is a step below the 7D Mark II for sure.