17-40mm ultra-wide-angle zoom lens with f/4 maximum aperture for Canon SLR cameras</br>3 aspherical lens elements and super UD glass element create superior optics in all conditions</br>Powerful ring-type ultra-sonic monitor (USM) produces fast and silent autofocusing</br>Focuses as close as 11 inches; supports screw-in 77mm filters or up to 3 gel filters</br>Suitable for Wedding/Nature Photography, Weather-resistant construction; measures 3.3 inches in diameter</br><br/>http://www.amazon.com/gp/product/B01BPH52V8