Nikon D850 User Manual page 292

f Controls
f1 Custom control assignment
Preview button
Preview button + y
Fn1 button
Fn1 button + y
Fn2 button
AF-ON button
Sub-selector
Sub-selector center
Sub-selector center + y
BKT button + y
Movie record button + y
Lens focus function buttons
f2 Multi selector center button
Shooting mode
Playback mode
Live view
f3 Shutter spd & aperture lock
Shutter speed lock
Aperture lock
268
Choose the roles assigned to camera
controls, either alone or in combination
with the command dials.
Choose the role played by the center of
the multi selector.
Lock shutter speed at the value
currently selected in mode S or M, or
aperture at the value currently selected
in mode A or M.