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Glossary of Terms (1)
Abbreviation used by Sigma to mark usage of Hyper-Sonic Motor in their lenses to achieve silent, high-speed AF. Usually contained in lens name eg. (18-50mm F2.8-4.5 DC OS HSM) Translated to Canon terminology it equals to USM (Ultrasonic Motor)Source:
Posted by: Radovan 24.02.2013 18:29:23