Nikon NIKKOR Z 70-200mm f/2.8 VR S Lens - Manual (Page 67)

43 Basic Photography and Playback
6
Focus.
To focus, press the shutter-release
button halfway or press the
AF-ON
button (the AF-assist illuminator may
light if the subject is poorly lit). If the
camera is able to focus, the focus
point will be displayed in green;
otherwise, the focus point will flash
red.
D The AF-Assist Illuminator
Do not obstruct the AF-assist illuminator while it is lit.