This large aperture telephoto macro lens incorporates Sigma's original Optical Stabilizer function. SLD glass elements provide excellent correction of all types of aberrations. Super Multi-Layer Coating reduces flare and ghosting and a floating inner focusing system provides high optical performance from infinity to 1:1 macro. The HSM (Hyper Sonic Motor) ensures quiet and high speed autofocus as well as full-time manual focusing capability. Attaching Sigma's optional Tele Converters enables photographers to shoot large than 1:1 magnification.