This ultra wide angle 15 30mm zoom lens continues tamrons development of lenses for serious photographers adding an ultra wide angle solution to their line up of high quality optics for pro dslr users suitable for full frame and smaller sensors the 15 30mm lens incorporates advanced features such as a constant f28 aperture throughout the zoom range along with quiet and fast usd ultrasonic silent drive focusing and water and dirt repellent fluorine coating on the new xgm front element th