If you could only have one lens many photographers would pick the upgraded EF 24-105mm f/4L IS II USM Lens from Canon due to its exceptionally versatile zoom range from wide-angle to short telephoto a constant f/4 aperture and an outstanding build quality befitting an L-series lens. This version II of the popular lens makes improvements to image quality through the use of a new optical design with four glass-molded aspherical elements which helps to limit vignetting in your images. Also it users an Air Sphere Coating to reduce ghosting and flaring.A ring-type Ultrasonic Motor AF system provides fast and accurate autofocus while built-in optical image stabilization can help compensate for about 4 stops of shutter speed minimizing the effects of camera shake. This lens also offers a zoom lock switch to prevent lens creep when not actively in use as well as an internal focus system. Full-time manual focus override is available for making adjustments regardless of the AF mode. Additionally it has a rounded 10-blade aperture diaphragm for smooth out of focus elements.As with all L-series lenses this optic has a dust- and water-resistant construction thanks to numerous seals that prevent intrusion when working in inclement weather. It also uses a fluorine coating on the exposed front and rear elements to help prevent smudges and make cleaning easier.Offering a versatile zoom range of 24-105mm this L-series lens is a staple of many shooters' kits. This updated version offers improved image quality with a notable enhancement in peripheral brightness.Designed for use with full-frame DSLRs this optic is compatible with APS-C format cameras as well where it will provide a 38.4-168mm equivalent focal length range.Constant f/4 maximum aperture offers consistent performance and light transmission throughout the zoom range.Four glass-molded aspherical elements including one large-diameter double-sided glass-molded lens help to minimize distortions throughout the zoom range in order to maintain edge-to-edge sharpness and illumination.An Air Sphere Coating (ASC) has been applied to lens elements to reduce backlit flaring and ghosting for maintained light transmission and high contrast in strong lighting conditions.A ring-type Ultrasonic Motor (USM) along with an internal focusing system high-speed CPU and optimized AF algorithms are employed to deliver fast precise and near-silent autofocus performance.Optical image stabilization minimizes the effects of camera shake by compensating for up to 4 stops of shutter speed.Full-time manual focus operation is available for fine-tuning of your focus position when working in the AF mode.Zoom lock prevents lens creep when not in use.A weather-resistant design protects the lens from dust and moisture to enable its use in inclement conditions. Additionally fluorine coatings have also been applied to the front and rear lens elements for further protection against fingerprints and smudging.Ten rounded diaphragm blades contribute to a pleasing out of focus quality that benefits the use of shallow depth of field and selective focus techniques.