Nikon PC-E NIKKOR 24mm f/3.5D ED Manuel D'utilisation page 30

The tilt function
En
By rotating the tilt knob, the lens is tilted up and down (or
right and left, when the lens is revolved) ±8.5° to the
camera body. By tilting, you can obtain clear focus of the
entire subject plane when it is not parallel to the camera or
can focus small areas of the subject which are parallel to
the camera (p. 207).
• After tilting, tighten the tilt lock release knob to fix the
lens' tilt position.
• Note that tilting the lens also changes the viewfinder
image.
• Once the lens is tilted, neither the depth-of-field scale nor
the distance scale on the lens barrel can be used.
Revolving
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Fig. 8
Fig. 9