East Wind Photography said:
Af system on the 1DX should have a 95-99% hit rate for this like birds in flight
5d3 about 95%
7d2 about 90-95%
I'll stop there as the less sophisticated AF systems drop off rapidly
Such generalisations are hokum to me (please don't take this personally).
As you cannot specify the situations in wich people shoot. Birds or bats or pigs in flight are not standardised procedures. Even as a maximum hit rate this percentages are not really reliable. Besides, the 7D2 has the autofocus system of the 1DX, so why should it be only equal or less good than the 5d3?
It should also be mentioned that the autofocus hit rate depends highly on the lens AF capabilities.
I tried a tamron 150-600 on a 5d3 and at 600mm f8 (max apt. f6.3) in continious AF it didn't even come close to 95% hit rate. But that was the lens (or my) "fault".
And with the 5D3 Tamron combination I had to do manual AF adjustment. Quite a lot of adujstment to be honest, it had enormous back focusing before. My 7D2 did not need any manual AF fine tuning with any lens I put on it so far (100mm f2.8; 100-400mm L II, Tamron 70-200 f2.8 )
There is a Tamron Firmware update that supposed to correct the 5D3 compatibility issue. Mine reacts the same way, but I have yet to send it in. The lens works great on my 7D2.