Use this to change the lens’s zoom setting – rotate the lens to the right (seen from above) to zoom in to a higher magnification and to the left to zoom out for a wider angle of view. On non-Nikon lenses the direction may be reversed, but it’s easy enough to see what’s going on by watching the focal length markings on the zoom ring as they line up with the index marker. The 18-105mm kit lens usually supplied with the D7200 has a longer zoom range than the 18-55mm lens usually supplied with cheaper models.