Nikon D500 - c: Timers;AE Lock

86 Menu Guide
Choose whether exposure locks when the shutter-release
button is pressed.
Choose how long the camera continues to meter exposure
when no operations are performed. The shutter-speed and
aperture displays in the control panel and viewfinder turn off
automatically when the standby timer expires.
Choose a shorter standby timer delay for longer battery life.
c: Timers/AE Lock
c1: Shutter-Release Button AE-L
G button ➜ A Custom Settings menu
Option Description
O
On (half press)
Pressing the shutter-release button halfway locks
exposure.
P
On (burst mode)
Exposure only locks while the shutter-release
button is pressed all the way down.
Off
Pressing the shutter-release button does not lock
exposure.
c2: Standby Timer
G button ➜ A Custom Settings menu