Canon EF 17-40mm 4.0L USM

Canon EF 17-40mm 4.0L USM

The Canon EF 17-40mm f/4.0L USM Lens is 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.

About half the price of the 16-35 f/2.8 lens, this L-series lens has an entirely new optical design with three Aspherical elements and a Super UD-glass element. The combination provides superb contrast and sharpness, even at the widest settings. It's ideal for both film and digital SLRs, and features the same weather-resistant design, rear gel filter holder, and high-speed Ultrasonic Motor as the EF 16-35mm lens. 

Features:

• EF mount; ultra-wide zoom lens
• Super Ultra-low Dispersion glass; inner focusing; aspherical lens; full-time manual focus
• 17-40mm focal length
• f/4.0 constant maximum aperture
• Ring-type UltraSonic Motor (USM)