Nikon Z 9 Reference Manual page 721

2
With the lens about ten centimeters (four inches) from a well-lit,
featureless white object, frame the object so that it fills the
display and then press the shutter-release button halfway.
•
In autofocus mode, focus will automatically be set to infinity.
•
In manual focus mode, set focus to infinity manually.
3
Press the shutter-release button the rest of the way down to
acquire Image Dust Off reference data.
•
The monitor turns off when the shutter-release button is pressed.
•
If the reference object is too bright or
too dark, the camera may be unable to
acquire Image Dust Off reference data,
in which case a message will appear and
the camera will return to the display
shown in Step 1. Choose another
reference object and press the shutter-
release button again.
B The Setup Menu: Camera Setup
721