Nikon Z fc N2016 Reference Manual page 246

exposure cannot be achieved at the value selected by the user in modes
P, S, A, and M.
Option
[ISO
sensitivity]
[Auto ISO
sensitivity
control]
[Maximum
sensitivity]
[Maximum
sensitivity with
c ]
C The photo shooting menu: Shooting options
The ISO sensitivity selected with the ISO sensitivity dial is
displayed.
Highlight [On] and press J to enable auto ISO
sensitivity control. If [Off] is selected, the ISO
sensitivity will remain fixed at the value selected with
the ISO sensitivity dial.
Choose the upper limit for auto ISO sensitivity control
to prevent it being raised too high.
Choose the upper ISO sensitivity limit for photos taken
using an optional flash unit.
Description
246