Canon EF 17-40mm f/4L USM Zoom Lens

Lens Type: Wide-angle zoom lens Mount: EF-mount (compatible with Canon full-frame and APS-C DSLR cameras) Focal Length: 17-40mm Aperture: Maximum aperture of f/4 Autofocus: Ultrasonic Motor (USM) for fast and silent autofocus Minimum Focus Distance: 0.28m (0.92 ft) Construction: 12 elements in 9 groups, including one Super UD lens and two aspherical elements Filter Size: 77mm Dimensions: 83.5 x 96.8mm (3.29 x 3.81 inches) Weight: 475g