Nikon D780 DSLR Camera (Body Only) - Manual (Page 718)

672 Menu Guide > B The Setup Menu
Record data for non-CPU lenses. Recording the focal length and
maximum aperture of non-CPU lenses allows them to be used
with some functions normally reserved for CPU lenses.
Non-CPU Lens Data
G button
U B setup menu
Option Description
[ Lens number ] Choose a number to identify the lens.
[ Focal length
(mm) ]
Enter the focal length.
[ Maximum
aperture
]
Enter the maximum aperture.