« on: February 16, 2015, 09:39:49 AM »
I have no axe to grind about FF vs crop or the 7DII vs 5DIII or the 100-400mm II vs big primes because I use combinations of all of them according to circumstances.
First, the AF on both my 5DIII and 7DII is fast and consistent in A1 servo, and my keeper rate is very high. The same was not true for my 7D, which could not even cope with some lens combination.
Second, I use the 5DIII + 300/2.8 II + 2xTC III for bird photography, accompanied by wife who uses the 7DII + 100-400mm II, both camera systems having about the same field of view. The quality of the images from the 7DII are excellent, though not quite as good from the 5DIII, despite the 100-400mm II not being in the same price league as the prime. My experience is that the 7DII + 100-400mm II at f/5.6 is as sharp at the centre as the Tamron-150-600mm on the 5DIII at f/8 and sharper at the edges.
I simply do not understand why some users are getting only 5% keepers and have AF problems. Some used to say the same about AF with Tamron 150-500 on the 5DIII, but I never had any problems. Perhaps I have been very lucky with my 7DII and 100-400mm II etc. But, whatever, some copies of the 7DII do really deliver the goods.