Upload & Sell: On
Erich, to spread the misery around a bit, I've got hundreds of photos from Saturday at Alliance where the 1DX + 200-400 f/4 failed to focus properly. Can't quite figure out if it's operator error or an AF malfunction, but I bet it's a little of both: I had the camera set for AI Servo (continuous AF) most of the day, but I do remember switching to Single Shot from time to time, so it's likely I just forgot to switch back and my panning bursts suffered as a result. However, there are some multi-frame bursts where the focus is just a tiny bit off and stays that way, even when the plane is first getting closer and then getting farther away throughout the pass, and it's the only thing in the frame: if it were set on Single Shot AF you'd expect the focus to get better or to get worse through the pass, but not stay the same. It's a mystery.