The Canon EF 70-200mm f/2.8L USM is not a new lens, but still offers very good performance on both full-frame and APS-C DSLRs. Optical construction includes four UD (ultra low-dispersion) elements to correct chromatic aberrations, and it is compatible with Canon's Extender EF 1.4x II and 2x II teleconverters. It's not to be confused with Canon's more expensive image-stabilised 70-200mm f/2.8 lenses.