- 17-40mm ultra-wide-angle zoom lens with f/4 maximum aperture for Canon SLR cameras
- 3 aspherical lens elements and super UD glass element create superior optics in all conditions
- Powerful ring-type ultra-sonic monitor (USM) produces fast and silent autofocusing
- Focuses as close as 11 inches; supports screw-in 77mm filters or up to 3 gel filters
- Weather-resistant construction; measures 3.3 inches in diameter; 1-year warranty
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