Nikon D850 User Manual page 377

❚❚ Zoom and Depth of Field
Before focusing, rotate the zoom ring to adjust the focal length
and frame the photograph. If the camera offers depth-of-field
preview (stop down), depth of field can be previewed in the
viewfinder.
Note: The lens uses Nikon's Internal Focusing (IF) system. Unlike
other lenses, focal length decreases as the focus distance
shortens. Note that the focus distance indicator is intended only
as a guide and may not accurately show the distance to the
subject and may, due to depth of field or other factors, not show
∞ when the camera is focused on a distant object.
❚❚ Aperture
Aperture is adjusted using camera controls.
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