Canon EF 17-40mm f/4L USM
A new and affordable L-series ultra-wide-angle zoom lens that's ideal for both film and digital SLRs. Superior optics are assured by the use of three Aspherical lens elements, in addition to a Super UD (Ultra-low Dispersion) glass element. Optical coatings are optimized for use with digital cameras. This lens focuses as close as 11 inches (0.28m), and offers both Canon's full-time manual focus and a powerful ring-type USM for fast and silent AF. It has a constant f/4 maximum aperture and offers the choice of screw-in 77mm filters or a holder in the rear of the lens for up to three gel filters. Finally, it offers weather-resistant construction similar to other high-end L-series lenses. Product Highlights EF Mount L-Series Lens Aperture Range: f/4-22 Three Aspherical Elements, One Super UD Ultrasonic Autofocus Motor Manual Focus Override Water and Dust Resistant Internal Zooming and Focusing Truly Circular Diaphragm 77mm Front Filter Diameter Rear Holder for Three Gel Filters Fit Models: 650D 700D 760D 70D 80D 7D 6D 5D2 5D3 1Dx T5i T3i T6 Dslr Camera The EF 17-40mm f/4L USM Lens from Canon is a high quality "L" series wide angle zoom lens for full frame and APS-C size DSLR cameras. It combines one high-precision molded glass aspherical element and two replica aspherical lenses to achieve the extended zoom range, while also correcting for common aberrations that arise during zooming. A Super UD (Ultra-low Dispersion) glass element minimizes the chromatic aberration of magnification which tends to occur with wide-angle lenses, to help eliminate color bleed along the edges of the subject and achieve high image contrast and resolution.