Good day,I recently came across a discussion stating that XT2 and ? XT3 cameras stop down a stop when C-Autofocussing. If this is correct does it mean that shooting at f8 eg. 100-400xf +1.4 TC(max zoom) will result in aperture stopdown to f9 and so result in loss of phase detection ability? Any comments and enlightenment would be much appreciated.