Canon 17-40MM L – Series
- EF Mount L-Series Lens
- Aperture Range: f/4-22
- Three Aspherical Elements, One Super UD
- Ultrasonic Autofocus Motor
- Manual Focus Override
- Water and Dust Resistant
- Internal Zooming and Focusing
- Truly Circular Diaphragm
- 77mm Front Filter Diameter
- Rear Holder for Three Gel Filters
The EF 17-40mm f/4L USM Lens from Canon is a high quality “L” series. Wide-angle zoom lens for full-frame and APS-C size DSLR cameras. It combines one high-precision molded glass aspherical element and two replica aspherical lenses to achieve the extended zoom range, while also correcting for common aberrations that arise during zooming.
A Super UD (Ultra-low Dispersion) glass element minimizes the chromatic aberration of magnification which tends to occur with wide-angle lenses, to help eliminate color bleed along the edges of the subject and achieve high image contrast and resolution.