The Sigma sd Quattro is an interchangeable-lens mirrorless camera body for SA mount lenses featuring the Foveon X3 Quattro APS-C sensor with 29 megapixels at the top layer for superior color accuracy and resolution. It uses the same H-shaped body design as the dp Quattro compacts and supports Sigma's full SA lens lineup. The sd Quattro is the APS-C variant in Sigma's sd Quattro mirrorless series.