What do the terms ED-IF, VR, DX, AF-S, etc. in Nikon/Nikkor lens mean?
ED – The lens uses Extra-low Dispersion glass for superior image quality, especially at wide apertures. IF – Internal Focus, focus is accomplished without the lens barrel rotating or changing length, an advantage when using a position-sensitive filter such as a polarizer. AF-S – Focusing is driven by a “Silent Wave” motor in the lens instead of the focus drive motor in the camera. AF-S lenses focus faster than standard AF-Nikkors and are almost completely silent. AF-S lenses with a “II” designation weigh less and are generally smaller than their equivalent predecessors. D – The lens provides Distance information to the camera electronically for more accurate light metering. G – The lens has no aperture control ring and is designed to be used with cameras that allow setting the aperture from the camera body. G lenses also provide Distance information to the camera. DC – Defocus Control, the optical characteristics of the lens can be altered to change the appearance of the out-of-focus e
