An 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
The Canon 17-40mm is commonly used for Art, Fun, General purpose, Landscape/scenery, Landscape photography, Low light, Night photography, Photojournalism, Portraits, Special effects, Sports/action, Travel, Upgrade, Video, Weddings, Wildlife, Wildlife photos and more.The Canon 17-40mm is most used by customers who consider themselves to be a Casual photographer, Enthusiast, Photo enthusiast, Professional, Pro photographer, Semi-professional, Semi-pro photographer among others.The Canon 17-40mm is popular because customers like the following qualities of the Canon 17-40mm: Clear glass, Consistent output, Durable, Easily interchangeable, Easily mounted, Easy to clean, Fast / accurate auto-focus, Lightweight, Nice bokeh, Rugged, Simple controls and Strong construction.