Silent Wave Motor
AF-S NIKKOR lenses feature Nikons Silent Wave Motor (SWM), which represents a significant advance in AF lens technology. SWM uses ultrasonicvibrationsrather than a gear systemto focus the lens, providing incredibly smooth, silent and precise autofocus operation.
ED (Extra-Low Dispersion) Glass
An optical glass developed by Nikon that is used with normal optical glass in telephoto lenses to obtain optimum correction of chromaticaberrations.
AS stands for Aspherical lens elements. This type of lens utilizes non-spherical surfaces on either one or both sides of the glass in order toeliminate certain types of lens aberration.
Select NIKKOR lenses have a focusing mode which allows switching from automatic to manual focusing with virtually no lag time by simply turning thefocusing ring on the lens. This makes it possible to seamlessly switch to fine manual focusing while looking through the viewfinder.
A NIKKOR lens in which only the internal lens group shifts during focusing. Thus, IF NIKKORS do not change in size during AF operation, allowingfor compact, lightweight lenses capable of closer focusing distances. These lenses will be designated with the abbreviation IF on the lens barrel.