Just got brand new D800 with 85 f1.8 and 24-120 f4. Moving from D7000. I spent 1 hour in the store playing with D600 and D800 and in the end chose the 800. Please, do not ask me why, the choice was more emotional, rather than rational.
Anyway, I mounted my 85 and took several pictures of my 14 months old son who was mostly running around just to test my new toy. Immediately noted that most of them were not sharp. Checked the files on my PC, most of them even did not have the focus point!
My settings were AF-C with 3D tracking, then I switched to Dynamic, 21 points, the custom setting for AF-C is focus and release. Most pictures were taken at 1/125s f/2.8 or f/4.
What am I doing wrong? Any advice would be appreciated.