Nikon D5 User Manual page 136

AF-S focus mode: Focus locks automatically when the in-focus
indicator (I) appears, and remains locked until you remove
your finger from the shutter-release button. Focus can also be
locked by pressing the center of the sub-selector as described
on the previous page.
3
Recompose the photograph
and shoot.
Focus will remain locked
between shots if you keep the
shutter-release button pressed
halfway (AF-S) or keep the center
of the sub-selector pressed, allowing several photographs in
succession to be taken at the same focus setting.
Do not change the distance between the camera and the subject
while focus lock is in effect. If the subject moves, focus again at the
new distance.
N
A
Locking Focus with the AF-ON Button
During viewfinder photography, focus can be locked using either of the
AF-ON buttons in place of the shutter-release button (0 102). If AF-ON
only is selected for Custom Setting a8 (AF activation, 0 329), the
camera will not focus when the shutter-release button is pressed
halfway; instead, the camera will focus when an AF-ON button is pressed,
at which point focus will lock and remain locked until either AF-ON
button is pressed again.
A
See Also
See Custom setting c1 (Shutter-release button AE-L, 0 334) for
information on using the shutter-release button to lock exposure.
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