24-105mm standard zoom lens with f/4 maximum aperture for Canon EOS SLR cameras * 1 Super UD glass element and 3 aspherical lenses minimize chromatic aberration and distortion * Ring-type USM system delivers silent but quick autofocus (AF); full-time manual focus * Image Stabilizer technology steadies camera shake at up to 3 stops; weighs 23.6 ounces * Dust- and moisture-resistant; measures 3.3 inches in diameter and 4.2 inches long * Ideal for handheld work, IS Image Stabilizer allows use of shutter speeds up to 3-stops slower with no perceptible increase in image blur. * With no change in aperture over the full focal length range, photographers can set exposure at the widest aperture and zoom through to 105mm without slowing shutter speed. * Ring USM (Ultrasonic motor) uses ultrasonic frequency vibrations to drive responsive, near-silent high speed auto focus. Good holding torque stops the focusing lens group with precision without overshoot. Full time manual focus override is available without having to switch out of AF.