Nikon Z fc N2016 Reference Manual page 144

Locking focus when AF-S is selected for focus mode or when AF-
D
A is selected and you are shooting in AF-S
Focus locks while the shutter-release button is pressed halfway. You can also
lock focus by pressing the A ( g ) button.
Locking exposure with the shutter-release button
D
If [On (half press)] is selected for Custom Setting c1 [Shutter-release button
AE-L], exposure will lock while the shutter-release button is pressed halfway.
Taking multiple shots at the same focus distance
D
･ If you locked focus by pressing the A ( g ) button, focus will remain
locked between shots if you keep the A ( g ) button pressed.
･ Focus will also remain locked if you keep the shutter-release button
pressed halfway between shots.
The A ( g ) button
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