The AF-S DX Zoom-Nikkor ED 12-24mm f/4G IF is a high-performance, internal focusing (IF) lens that uses a Silent Wave Motor to drive the focusing mechanism, hence the “S” designation. As a result, autofocusing is smooth, silent, and almost instantaneous. Autofocus (A) or manual (M) mode can easily be selected with the focus mode switch. Autofocusing with manual override is provided, allowing instant change from autofocusing to manual focusing. More accurate exposure control is possible when this is mounted on a Nikon camera.