I finally managed to get outside today and try to get the hang of the multitude of ai servo focusing options on the 1dx. These photos were taken using all 61 focus points with the intelligent tracking system. The camera recognises the primary subject and then tracks focus on that subject, based on its initial calculations using shape and colour. It tracks amazingly well and most shots were within acceptable limits. I have the autofocus option set for erratic moving subjects which did work better than the stock standard setting. In hindsight I should have set it on the accelerating/decelerating setting for my dog Allie. I think it will be even better if I use the 1 point autofocus option
She runs like the wind and I really want to capture her at full speed. Once I get the exact setting mastered I'll get it right. In the meantime here are few I took this afternoon. My early assessment is that the autofocus system on this camera is going to be in a league of its own. It is a lot more intuitive than the 1D iv and the camera is a little easier to use.