Nikon D330018-55VR User Manual (en)

Technical Notes
Identifying CPU and Type G, E, and D Lenses
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
Aperture ring
CPU lens
Type G or E lens
Type D lens
When using a CPU lens equipped with an aperture ring, lock the 
aperture ring at the minimum aperture (highest f-number).
Matrix Metering
For matrix metering, the camera uses a 420-pixel RGB sensor to set 
exposure according to tone distribution, color, composition, and, with 
type G, E, or D lenses, distance information (3D color matrix metering 
II; with other CPU lenses, the camera uses color matrix metering II; 
which does not include 3D distance information).