Sigma 70mm F/2.8 EX DG Macro Lens for Canon Digital SLR Cameras Special Low Dispersion (SLD) lens and two high refractive index SLD lenses provide excellent correction for all types of aberrations Super multi-layer lens coating reduces flare and ghosting Floating focus system provides extremely high optical performance from infinity to 1:1 Macro Equivalent field of view to 105mm macro lens when used on a digital SLR camera with an APS-C size image sensor