Nikon Camera N90 - Manual (Page 49)

AUTOFOCUS
The Nikon N90 has two autofocus modes, Single Servo AF with
Focus-Priority and Continuous Servo AF with Release-Priority.
In either autofocus mode and in any film advance mode, Focus
Tracking automatically activates when the subject starts
moving. Focus Tracking enables the camera to analyze the
speed of the moving subject according to the focus data
detected, and to obtain correct focus by anticipating the
subject’s position—and driving the lens to that position—at the
exact moment of exposure. You can thus obtain correctly
focused pictures for many moving subjects.
Data Link System users
You can give Focus-Priority to Continuous Servo AF
and/or Release-Priority to Single Servo AF.
For Single Servo AF in continuous shooting, you can also
cancel focus detection and lens driving for the next shot
after the first shot is taken so that the subject focus
remains locked.
For details, see the Nikon AC-1 E card's instruction
manual.