This lens features completely redesigned optics, including two high-precision Aspherical elements and two UD-glass elements. This results in better contrast and sharpness at the outer edges, and a reduction in chromatic aberrations that can sometimes be seen with high-resolution digital SLRs.
The optical design incorporates two aspherical elements and two ultra-low dispersion elements to control both spherical and chromatic aberrations in order to realize a high degree of sharpness, clarity, and color accuracy. A Super Spectra coating has also been applied to suppress flare and ghosting for increased contrast and color fidelity when working in backlit and harsh lighting conditions.
A ring-type USM and internal focusing mechanism also afford quick, quiet, and accurate autofocus performance, as well as full-time manual focus override. Additionally, this lens is weather-sealed for use in trying climates.