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-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.
A NIKKOR lens in which only the internal lens group shifts during focusing. These lenses will be designated with the abbreviation IF on the lens barrel.