Sigma 105mm f/2.8 EX DG Medium Telephoto Macro Lens for Canon SLR Cameras Compact and lightweight medium telephoto macro lens. Optimized image quality for Digital SLR cameras. Maximum magnification of 1:1 Focus Limiter Switch that limits the AF range so improving the speed and accuracy of auto focus Dual Focus (DF) system that is designed to make the lens easy to hold during auto focusing