Upload & Sell: On
I asked a question earlier about autofocus on the D4/D800 (here). I've got a more general question about autofocus though that I'm hoping for some help on:
What's the difference between 51-point dynamic-area AF and 3D tracking?
In the manual is this:
51-point: "Choose when photographing subjects that are moving quickly and can not be easily framed in the viewfinder (e.g., birds)."
3D tracking: "...the camera will track subjects that leave the selected focus point and select new focus points as required. Use to quickly compose pictures with subjects that are moving erratically from side to side (e.g., tennis players)"
That sounds pretty similar to me. In 51-point mode, if I focus on an object, then pan the camera, I see the object stay in focus (despite the original focus point still being highlighted). If I review the photo on the camera (with the option to see focus points on), I can see that a different focus point actually as been selected.
So what is the benefit of 3D tracking when would you use it instead of dynamic AF?