Nikon lens, what do you mean by D and G? What is the difference?

D-head is Nikon's early automatic lens with an aperture ring, which can be set manually or automatically. G-head is Nikon's new generation automatic lens, which has no aperture ring and can only be set through the fuselage. D head can be used on Nikon's full range of fuselage, and G head can't be used on some old film machines.

Distance/size information. Support Nikon's new 3D matrix photometry. During the exposure measurement, the lens can be transmitted to the camera together with the distance data, and it helps to determine a more accurate exposure value. And because it is equipped with an independent aperture ring, it is compatible with manual camera product series.

G- is a lens that can realize aperture adjustment in the camera body. The lens has no independent aperture ring and is light in weight. But it can only be used for fuselage with motor. It has the same characteristics as the D series lens.