Nikon D5 User Manual page 438

A
Recognizing CPU and Type G, E, and D Lenses
CPU lenses (particularly types G, E, and D) are recommended, but note
that IX-NIKKOR lenses can not be used. CPU lenses can be identified by
the presence of CPU contacts, type G, E, and D lenses by a letter on the
lens barrel. Type G and E lenses are not equipped with a lens aperture
ring.
CPU contacts
CPU lens
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Lens f-number
The f-number given in lens names is the maximum aperture of the lens.
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Compatible Non-CPU Lenses
Non-CPU lens data (0 241) can be used to enable many of the features
available with CPU lenses, including color matrix metering; if no data are
provided, center-weighted metering will be used in place of color matrix
metering, while if the maximum aperture is not provided, the camera
aperture display will show the number of stops from maximum aperture
and the actual aperture value must be read off the lens aperture ring.
n
414
Type G/E lens
Aperture ring
Type D lens