Nikon D3body D3 User's Manual - Page 333

Option Description If the subject leaves the selected focus point, the camera will use 3D-tracking to track the subject f 51 points (3D-tracking) and select a new focus point as required. Use to quickly compose pictures with subjects that are moving erratically from side to side (e.g., tennis players). If the subject leaves the viewfinder, remove your finger from the shutter-release button and recompose the photograph with the subject in the selected focus point. A 3D-Tracking When the shutter-release button is pressed halfway, the colors in the area surrounding the focus point are stored in the camera. Consequently 3Dtracking may not produce the desired results with subjects that are the same color as the background or that occupy a very small area of the frame. U 307