 "WCL-X100 Wide-Angle Conversion Lens for X100 Camera (Silver)"
 "Canon EF 17-40mm f/4 L USM Lens"@en "Camera Lenses :: Canon Lens - Onestop Digital"@en
"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 f4 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.  "@en 