The Canon EF 17 - 40 mm F4.0 L lens is designed for both film and D-SLR cameras. This ultra-wide-angle zoom lens has weather-resistant construction of 12 elements in 9 groups. The lens has Super Spectra coating and has 7 diaphragm blades. The maximum angle of view provided by this Canon lens is 104 degrees.
The focal length of the lens is 17 - 40 mm and it has Aperture of F/4.0. This Canon lens weighs 500 g and has dimensions of 83.5 x 96.8 mm. The maximum magnification attained by the lens is 0.24x. The lens has Manual Zoom option and can Optically Zoom up to 2.4x. The lens has filter attachment size of 77 mm. User can avail both full time Manual focusing and Auto Focusing with this lens. This Canon lens has closest focusing distance of 0.28 m.
The Canon EF 17 - 40 mm F4.0 L lens can be used on Canon EF mount. The lens uses inner focusing system with Ultrasonic Motor (USM).