Nikkor 300mm f/4.5 ED IF AI-S is a manual focus telephoto prime lens. During its time, the 300mm was the lightest 300mm in Nikon's lens line up. This lens employs internal focusing and Extra-low Dispersion glass element. Its internal focusing technology enables the lens elements to move inside the lens and prevents movement of the lens barrel as the lens is focused closer. The optical construction of seven elements in six groups including one ED glass element to produce superior sharpness and color correction by reducing chromatic aberration. The lens includes a rotatable and removable tripod collar, nine blade diaphragm, 8.2ft close focus distance, 8°10' picture angle and 72mm filter thread.