Sigma APO 70-200mm f/2.8 EX DG HSM Lens for Canon Digital SLR Cameras 70-200mm focal length 105-300mm equivalent focal length on APS-C cameras, 140-400mm equivalent focal length on Four Thirds / Micro Four Thirds cameras, 112-320mm equivalent focal length on Canon APS-C cameras F2.8 constant maximum aperture; F22 minimum Ring-type ultrasonic-type AF motor with full-time manual focusing 77mm filters 1.00m/39.37" minimum focus Available in Canon EF, Four Thirds, Pentax KAF3, Sony Alpha, Sigma SA, Nikon F (FX) mounts Large Aperture Zoon Macro. Fast Auto-Focus Super Sharp