THe D600 is VERY unforgiving when it comes to getting off the subject and back on, or dealing with very fast subjects moving right at the camera as they get closer. I don't think it's feeding the information to the lens fast enough. I've had the same problem on some of my older pro bodies occasionally.
I typically shoot AF-C, 21pt, using the center or nearly center focus points. Focusing tracking is set to off. This gives me great results 95% of the time. Occasionally, I miss things. Nature of the beast. If it was a huge deal to me, I'd buy a D4.
>Regarding your basketball shoots. I have been shooting a >nationally ranked HS this season (very fast and agile)with my >new D600. Primarily shooting with an 85 f 1.8 D -- from the >baseline. When the shots are great, they are really great, >but I have more oof than I would like, especially on plays >when a guard is sprinting down the court, at me. Every APC >combination I have experimented with seems more than willing >to see the audience and focus on it. So the first shot is ok, >then oof. Funny, if I shoot less, sometimes I get a shot back >in focus again. > >So I ask, what AF specs are you using? > >Thanks > >John