Beyond the bokeh-optimized design, the optical layout of this lens incorporates a Blue Spectrum Refractive Optics element; a specially developed element that helps to nearly eliminate chromatic aberrations and color fringing for notable clarity and color accuracy. In addition to this, an ultra-low dispersion element and one aspherical element are also featured to further control various aberrations and distortion for great sharpness and resolution. Individual elements also feature an Air Sphere Coating to suppress flare and ghosting for high contrast and color fidelity when working in bright and backlit conditions.
Complementing the imaging capabilities is an apt ring-type Ultrasonic Motor, which delivers fast, near-silent autofocus and full-time manual focus override. A unique Control Ring is also integrated into the lens design for intuitive control over exposure settings from the lens itself.
Portrait-length prime is designed for full-frame Canon RF-mount mirrorless digital cameras.
Exceptionally bright f/1.2 maximum aperture affords extensive control over depth of field for selective focus applications and also benefits working in low-light situations.
Defocus Smoothing coating helps to achieve an especially soft and smooth bokeh quality when working at wide aperture positions. While this coating softens the look and feel of the out-of-focus regions in an image, sharpness is still retained on the in-focus portions for noticeable subject separation and an overall three-dimensional quality. The effect is greatest when working at f/1.2, however the DS coating requires approximately 1.3 stops more exposure than the standard version of the lens when shooting wide open. By f/3.2, the two versions of the lens have nearly identical light transmission and performance.Blue Spectrum Refractive Optics element virtually eliminates color fringing and chromatic aberrations by refracting shorter wavelengths of the visible spectrum (blue light). One aspherical element and one UD element also help to control aberrations and distortions for sharper, clearer image quality.
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.
Ring-type Ultrasonic Motor (USM), along with optimized focusing algorithms, a high-speed CPU, and an internal focusing design, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override.
Configurable Control Ring can be used to adjust a variety of exposure settings, including aperture, ISO, and exposure compensation.
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 9-blade diaphragm contributes to a pleasing bokeh quality.