Long Exposure Nr; [Long Exposure Nr] - Nikon Z 9 Reference Manual

Long Exposure NR

Select [ON] to reduce "noise" (bright spots or fog) in photographs taken
at shutter speeds slower than 1 s.
•
Long-exposure noise reduction is performed after the photo is taken.
During processing, the message, "[Performing noise reduction]" will
appear in the shooting display and "Job NR" will flash in the control
panel. Pictures cannot be taken until the message has cleared from
the display. The time required to process photos after shooting
roughly doubles.
D
Caution: Long-Exposure Noise Reduction
If the camera is turned off before processing is complete, the picture will be
saved but noise reduction will not be performed.
C The Photo Shooting Menu: Shooting Options
514
G button U C photo shooting menu
Control panel Monitor