Wide-angle zoom lens is designed for use with full-frame Canon RF-mount mirrorless cameras. Constant f/2.8 maximum aperture maintains consistent illumination throughout the zoom range and suits working in available light conditions. Two UD (Ultra-Low Dispersion) elements help to minimize chromatic aberrations and color fringing in order to provide greater clarity and color accuracy. Three aspherical elements are used to correct spherical aberrations and distortion for improved sharpness and accurate rendering. An Air-Sphere Coating (ASC) has been applied to lens elements to reduce backlit flaring and ghosting for maintained light transmission and high contrast in strong lighting conditions. An Optical Image Stabilizer helps to minimize the appearance of camera shake by five stops to better enable working in low-light conditions and with slower shutter speeds. Nano USM system utilizes both a ring type USM and an STM mechanism to realize quick and accurate focusing that is also smooth and nearly silent to suit both photography and video applications. This focusing system also affords full-time manual focus control when working in the one-shot AF mode. Configurable Control Ring can be used to adjust a variety of exposure settings, including aperture, ISO, and exposure compensation. Protective fluorine coating has been applied to the front and rear element to resist fingerprints and smudges and to make cleaning these elements significantly easier. As a member of the esteemed L-series, this lens has a weather-resistant design that protects against dust and moisture to enable its use in inclement conditions. Rounded nine-blade diaphragm contributes to a pleasing bokeh quality.