Nikon D300 User Manual page 262

Let's examine the 9, 21, 51, and
patterns:
▪ 9 points – Use this setting when the movement of your
subject is predictable. This setting uses an array of 8 AF
points surrounding your selected and viewable AF point.
Good subjects for this mode may be a car race or air
show.
▪ 21 points – If your subject is moving unpredictably, this
may be your best choice. This uses 20 AF points
surrounding your viewable point. Good subjects for this
setting might be players in a football or basketball game.
▪ 51 points – This is for worst-case scenario subjects that
are small or move rapidly and unpredictably—to the
point that it is even hard to keep them in the Viewfinder.
All 50 sensors surrounding your selected sensor are
active. A good subject might be a bird in flight. (See the
upcoming sidebar called
Slower Autofocus Response
▪ 51 points (3D-tracking) – This mode is very similar to
regular 51
mix. It remembers the color of your subject and tries to
maintain the focus with this extra help.
Here are the screens and steps to select one of the four pattern
types (Figure 4-8):
points, except that it adds color tracking to the
262
51 point (3D-tracking)
More AF Points Can Mean
Time.)