Nikon D850 User Manual page 319

• SB-700: AF-assist illumination is available when 24–135 mm AF lenses
are used with the focus points shown below.
Focal length
24–27 mm 28–135 mm
Depending on the lens used and scene recorded, the in-focus indicator
(I) may be displayed when the subject is not in focus, or the camera
may be unable to focus and the shutter release will be disabled.
A
Optional Flash Units
In i-TTL and auto aperture (qA) flash control modes, the flash
compensation selected with the optional flash unit or the Flash
control option in the photo shooting menu is added to the flash
compensation selected with the W (M) button and command dial.
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