Canon EF 17-40mm f/4L USM

Canon EF 17-40mm 4.0 L USM wide-angle lens

The EF 17-40mm F/4 L USM is a wide-angle Canon EF zoom lens designed for professional and advanced EOS series SLR camera users.

While the EF 17-40mm f/4 L USM is an excellent lens for analogue SLR cameras, it is also particularly well suited for digital SLR cameras, which have image sensors smaller than the frame of a 35mm film camera. In such digital cameras, the lens' focal lengths produce an angle of view roughly equivalent to a 28-70mm lens on a 35mm camera. This makes it an ideal entry-level zoom for digital SLR cameras.

The EF 17-40mm F4L USM consists of twelve lens elements arranged in nine groups. The elements are coated with Super Spectra coatings for excellent color balance and reduced ghosting and flare. To ensure excellent image quality throughout the 17-40mm zoom range, the lens features three aspherical elements of two different types, and Super UD (Ultra-low Dispersion) glass to prevent chromatic aberrations, which often reduce the clarity of subject edges.

• Excellent optical properties throughout the zoom range
• Good dust and moisture protection
• Closest focusing distance 28 cm at all focal lengths