Complementing the optical design is a sophisticated focusing system, which uses a DC motor, Silent Drive module, GMR magnetic sensor, and an internal focusing design in order to provide especially quiet and quick focusing performance to suit stills and video needs. A One-Touch Focus Clutch Mechanism also allows for fast switching between autofocus and manual focus settings. Additionally, this 16-28mm f/2.8 sports a nine-blade diaphragm to produce a pleasing bokeh quality and it has a built-in lens hood to shield the bulbous front element from stray light.
- Wide-angle zoom is designed for full-frame Canon EF-mount cameras, however can also be used with APS-C models where it provides a 25.6-44.8mm equivalent focal length range.
- Constant f/2.8 maximum aperture offers consistent performance and excellent light transmission throughout the zoom range.
- Three aspherical elements are used to reduce spherical aberrations and distortion in order to realize sharp imagery with accurate rendering.
- Three glass-molded low dispersion elements greatly reduce color fringing and chromatic aberrations in order to produce greater clarity and color accuracy.
- Bulbous front element contributes to realizing low distortion and even illumination across the frame.
- Multi-coating has been applied to individual elements to suppress flare and ghosting in order to achieve greater contrast and color fidelity when working in strong lighting conditions.
- A DC motor, along with a Silent Drive module, GMR magnetic AF sensor, and internal focusing design, affords especially quiet, precise, and fast autofocus performance. Additionally, a One-Touch Focus Clutch Mechanism permits switching between AF and MF modes by simply snapping the focus ring back and forth.
- Built-in petal-shaped lens hood helps to prevent stray light from causing flare and also offers some protection to the front lens element.
- Nine-blade diaphragm promotes a pleasing out of focus quality that benefits the use of shallow depth of field techniques.