Nikon D850 User Manual page 123

A
The AF-ON Button
For the purpose of focusing the camera,
pressing the AF-ON button has the same
effect as pressing the shutter-release button
halfway.
A
Predictive Focus Tracking
In AF-C mode, the camera will initiate predictive focus tracking if the
subject moves toward or away from the camera while the shutter-
release button is pressed halfway or the AF-ON button is pressed. This
allows the camera to track focus while attempting to predict where the
subject will be when the shutter is released.
A
See Also
For information on:
• Using focus priority in continuous-servo AF, see A > Custom Setting
a1 (AF-C priority selection, 0 260).
• Using release priority in single-servo AF, see A > Custom Setting a2
(AF-S priority selection, 0 260).
• Preventing the camera from focusing when the shutter-release
button is pressed halfway, see A > Custom Setting a8 (AF activation,
0 261).
• Limiting focus-mode selection to AF-S or AF-C, see A > Custom Setting
a10 (Autofocus mode restrictions, 0 262).
• Using the sub-command dial to choose the focus mode, see A >
Custom Setting f4 (Customize command dials) > Change main/sub
(0 269).
• The autofocus options available in live view or during movie
recording, see "Autofocus" (0 41).
AF-ON button
99