The EF 24-105mm f/4L IS USM Lens from Canon ;is a versatile, ;easy-to-use standard zoom lens that covers a ;focal range from wide-angle to portrait-length telephoto. Its constant maximum aperture of f/4 provides effective consistency when at the telephoto end of the zoom range. The L-series is Canon's flagship professional lens series, combining the highest standards of precision optics and operability with dust and moisture resistant construction. Canon's ring-type Ultrasonic Motor (USM) ;provides silent ;and quick ;autofocus as well as full-time manual focus override. Optical image stabilization enables up to 3-stops of compensation against the effects of camera shake and one Super-UD and three aspherical lens elements minimize aberrations for overall optical clarity. With ;impeccable construction and comfortable handling, this is a durable yet sophisticated lens that meets the demands of advanced amateur photographers and professional photographers alike.