Nikon D300S User Manual page 291

Option
d 21 points
e 51 points
f 51 points
(3D-tracking)
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 3D-tracking 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.
If the subject leaves the selected focus point, the
camera will focus based on information from the
surrounding 20 focus points. Choose when
photographing subjects that are moving
unpredictably (e.g., players at a football game).
If the subject leaves the selected focus point, the
camera will focus based on information from the
surrounding 50 focus points. Choose when
photographing subjects that are moving quickly and
can not be easily framed in the viewfinder (e.g., birds).
If the subject leaves the selected focus point, the
camera will use 3D-tracking to track the subject 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.
Description
U
265