Ultrasonic Motor (USM) for fast and near silent auto focus.
Full-time manual focus override.
Super Spectra coatings and optimised lens element shaping to suppress flare and ghosting.
Environmental seals providing dust and moisture resistance.
Circular aperture diaphragm for beautifully even background bokeh and 'removal' of distracting backgrounds.
Distance information passed back to the new E-TTL II flash algorithm of all current model digital EOS cameras.
Minimum focus distance 45cm.
Lens hood and pouch included in the box.

Focal Length : 50mm
Maximum Aperture : 1.2
Minimum aperture : 16
Lens Construction : 8 elements in 6 groups
Diagonal Angle of View : 46o (with full-frame cameras)
Focus Adjustment : AF with full-time manual
Closest Focusing Distance : 1.48 ft. / 0.45m
Filter Size : 72mm
Dimensions (D x L) : 85.4mm x 65.5mm (3.4 in. x 2.6 in.)
Weight : 545g (19.2 oz) (lens only)