Nikon Z fc N2016 Reference Manual page 247

Option
[Minimum
shutter speed]
･ When auto ISO sensitivity control is enabled, the shooting display will
show ISO AUTO. When sensitivity is altered from the value selected
by the user, the ISO sensitivity will be shown in the displays.
C The photo shooting menu: Shooting options
Choose the shutter speed (1/4000 to 30 s) below
which auto ISO sensitivity control will kick in to
prevent underexposure in modes P and A. If [Auto] is
selected, the camera will choose the minimum shutter
speed based on lens focal length. For example, the
camera will automatically choose faster minimum
shutter speeds to prevent blur caused by camera
shake when a long lens is attached.
･ To view auto shutter-speed selection options, highlight
[Auto] and press 2. Auto shutter-speed selection can
be fine-tuned by choosing faster or slower minimums.
Faster settings can be used to reduce blur when
photographing fast-moving subjects.
･ Shutter speeds may drop below the selected minimum
if optimal exposure cannot be achieved at the ISO
sensitivity chosen for [Maximum sensitivity].
Description
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