In addition to two large-diameter double-surface aspherical GMo lenses, this lens employs one ground aspherical lens and two UD lenses to achieve high-quality images from the center to the periphery throughout the entire zooming range. This lens provides high-contrast depiction with clear edges from corner to corner of the image. Moreover, SWC and ASC technologies effectively suppress the occurrence of ghosting and flare. Thanks to the enhanced durability of the lens body, this large-diameter wide-angle zoom lens is capable of remarkable performance that exceeds that of its predecessor, in terms of image quality, handling ease, reliability, and more.
- Excellent environmental resistance
- Dust-proof, drip-proof structure is applied to the mount, switch panel, zoom ring, and focusing ring.* A fluorine coating is applied to the foremost and rearmost lens surfaces to make it easy to remove dirt from the lenses.
* Since the front lens portion moves during zooming, a Canon Protect Filter (sold separately) must be mounted to ensure adequate resistance to dust and dripping. Complete prevention of extraneous materials from entering the lens body is not guaranteed. - Enhanced rigidity and durability
- A renewed mechanical structure accommodates the requirements of rugged use and a newly developed optical system, resulting in improved vibration-resistant, shock-resistant performance that is expected of a new-generation L lens. Also, a new lens barrel structure is adopted to improve durability of the lens.
- High-speed autofocus
- High-speed, high-precision autofocusing is made possible by optimally matching USM control via inner focusing system, high-performance CPU of the lens, and the camera’s AF algorithm.

Specifications Comparison
EF16-35mm f/2.8L II USM | EF16-35mm f/2.8L III USM | |
---|---|---|
Focal length | 16-35mm | 16-35mm |
Maximum aperture | f/2.8 | f/2.8 |
Construction (groups-elements) |
16 elements in 12 groups | 16 elements in 11 groups |
No. of diaphragm blades | 7 | 9 |
Minimum aperture | 22 | 22 |
Closest focusing distance | 0.28m/0.92ft | 0.28m/0.92ft |
Maximum magnification | 0.22x (at 35mm) | 0.25x (at 35mm) |
Filter size | 82mm | 82mm |
Max. diameter x length | φ88.5×111.6mm / φ3.5×4.4 in. | φ88.5×127.5mm / φ3.48×5.02 in. |
Weight | Approx. 640g | Approx. 790g |
