A-M stands for Auto-Manual Mode. Thanks to a mechanism incorporated in the lens barrel, smooth focusing operation in Manual focus mode is realized in the same way as users have become accustomed to with conventional manual-focus lenses by adding an appropriate torque to the focus ring.
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 to eliminate certain types of lens aberration.
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 chromatic aberrations.
A NIKKOR lens in which only the internal lens group shifts during focusing. Thus, IF NIKKORS do not change in size during AF operation, allowing for compact, lightweight lenses capable of closer focusing distances. These lenses will be designated with the abbreviation IF on the lens barrel.
Silent Wave Motor
AF-S NIKKOR lenses feature Nikon’s Silent Wave Motor (SWM), which represents a significant advance in AF lens technology. SWM uses ultrasonic vibrations—rather than a gear system—to focus the lens, providing incredibly smooth, silent and precise autofocus operation.
A Nikon in-lens technology that improves image stability by automatically compensating for camera shake. Lenses that offer VR will feature the abbreviation VR on the lens barrel.