This lens employs an IF (Internal Focusing) system that maintains the overall length of the lens during focusing. Uses two LD (Low Dispersion) glass elements that effectively compensate for chromatic aberration. Provides high-contrast, outstanding image quality and a soft out-of-focus background effect. Incorporates an AF/MF one touch switchover mechanism built into the focus ring(for Canon & Nikon only). Super performance series provides high performance through outstanding design specifications.