Nikon Z 5 Reference Manual page 316

D
Exposure Bracketing
The settings (shutter speed and/or aperture) altered during exposure
bracketing vary with the shooting mode.
Mode
P
S
A
M
1 If [On] is selected for [ISO sensitivity settings] > [Auto ISO
sensitivity control] in the photo shooting menu, the camera will
automatically vary ISO sensitivity for optimum exposure when the
limits of the camera exposure system are exceeded.
2 If [On] is selected for [ISO sensitivity settings] > [Auto ISO
sensitivity control] in the photo shooting menu, the camera will first
use auto ISO sensitivity control to bring exposure as close as possible
to the optimum and then bracket this exposure by varying shutter
speed.
3 Use Custom Setting e6 [Auto bracketing (mode M)] to choose
whether the camera varies shutter speed, aperture, or both shutter
speed and aperture.
C The Photo Shooting Menu: Shooting Options
274
Setting
Shutter speed and aperture
Aperture
Shutter speed
Shutter speed
1
1
1
2, 3