I have been using both zooms for several months and have consistently noticed AF inaccuracies. Here are my observations:
24-70: At close distance from MFD to around 4-5 meters, focus is right on, however at infinity there is an evident front focusing that requires an AF adjustment of +5 for sharpest results. The problem is that the close distance focusing is no longer accurate as it back focuses. The lens seems to be calibrated for closer distances.
16-35: Seems to be calibrated for infinity, where it is spot on. At closer distances, it back focuses, which brings me to exactly the same problem, as when I adjust AF to get sharpest results at close distances, it front focuses at infinity
I am not sure if this camera related, but all other lenses focus perfectly. I suspect that Sony has calibrated the lenses for best results taking in consideration the field curvature, but I'm not really sure about that.
The fact remains, both zooms seem to be unable to AF accurately at either close or far distance. Adjusting one will screw up the other.
I wonder if any of you guys has experienced the same.