A tremendously flexible standard zoom for APS-C-format DSLRs, the EF-S 17-55mm f/2.8 IS USM from Canon pairs the 27.2-88mm equivalent focal length range with a bright f/2.8 constant maximum aperture. Benefitting this design is a sophisticated optical layout, which includes both Ultra-Low Dispersion glass and aspherical elements to significantly reduce chromatic and spherical aberrations for improved clarity and sharpness throughout the zoom range. A Super Spectra coating has also been applied to individual elements to suppress flare and ghosting for increased contrast when working in bright environments. Beyond the optical attributes, this 17-55mm is also characterized by its advanced three stop-effective Image Stabilizer system to minimize the appearance of camera shake. Also complementing handling is a sophisticated ring-type USM, which provides quick, quiet, and accurate autofocus performance along with full-time manual focus override.

EF-S Mount Lens 27-88mm (35mm Equivalent) Aperture Range: f/2.8-22 UD and Aspherical Lens Elements Optical Image Stabilization Ultrasonic Autofocus Motor Manual Focus Override Truly Circular Diaphragm Minimum Focus Distance: 1.2' 77mm Filter Thread Diameter

My favorite standard zoom for the c300 / doc shooting.

Canon 17-55mm 2.8 with IS

Canon EF-S 17-55mm f/2.8 IS USM

Includes: Lens Hood, Lens Bag

A fantastic all-purpose zoom lens. The EF-S 17-55mm f/2.8 IS USM Lens from Canon is a large-aperture lens compatible with APS-C format digital SLR cameras, and offers a versatile wide-angle to short telephoto zoom range. The focal length is equivalent to approximately 27-88mm in 35mm format and its constant f/2.8 maximum aperture is effective in low light throughout the zoom range. A wide maximum aperture also enables shallow depth of field control. This lens features Canon's optical Image Stabilizer technology, providing up to 3-stop compensation for image blur caused by camera shake at slow shutter speeds. This enables clear images, even in dim light. An ultrasonic autofocus motor (USM) provides fast and quiet AF action which is particularly important when shooting video and manual focus override allows precise manual focus at any moment, even in autofocus mode. A fast, constant maximum aperture of f/2.8 is ideal for low light shooting, utilizing fast shutter speeds and for shallow depth of field control. Optical image stabilization enables up to 3 shutter speed stops of blur compensation to create clearer images when shooting handheld and in low light situations. Ring-type Ultrasonic Autofocus Motor (USM) provides quiet, fast, precise auto focusing and predictive tracking. Features three aspherical lens elements (two types) as well as a UD glass element for reduced aberrations and high image quality at all focal lengths. Optimized lens coating minimizes flare and ghosting prone to occur with digital cameras. Internal focusing and new AF algorithms improve AF speed and with full-time manual focus override allows precise manual focus even in AF mode. Uses optics designed to take full advantage of the small image circle and short back focus in EF-S lenses. Circular aperture diaphragm produces brilliant out-of-focus characteristics