I've happened to shoot portrait sessions with the DFA* 70-200 where I had to actually
reduce the sharpness in final post processing ...
Don't know, maybe there are sharper lenses for details at infinity... or maybe someone should have used contrast AF on both cameras for comparison?..
Phase AF on Pentax cameras has little to do with the quality of the lens.
For my money, DFA* 70-200 is by far the
best 70-200 lens for portraiture, and one of my two favorite Pentax glass of all time.
Tamron SP 70-200 2.8 G2, for one, has very much the same focus breathing issues yet it has been extremely well received by pros and consumers alike. What is alarming in the current technical extasy over sharpness and micro contrast is that it kills the 'air', the 3D aspect in the picture. Sharpness is not as important as resolution...