The EF 135mm f/2L USM is a medium telephoto prime and a member of Canon's L-series of lenses. The long focal length coupled with the f/2 maximum aperture affords a great deal of control over depth of field for isolating subject matter and using selective focus, and the bright aperture also benefits shooting handheld in low-light conditions. In regard to the optical design, the lens uses two ultra-low dispersion elements to control chromatic aberrations and color fringing for high clarity, and a Super Spectra coating has also been applied to suppress flare and ghosting for increased contrast and color accuracy. Medium-length telephoto prime is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 216mm equivalent focal length. Two ultra-low dispersion (UD) elements greatly reduce chromatic aberrations and color fringing for improved clarity and color accuracy. A ring-type Ultrasonic Motor (USM), along with a rear focusing system, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override.
Canon EF 135mm F/2L USM Specs