The Sigma 12-24mm f/4 DG HSM Art Lens is an ingenious tool that enables you to take high-resolution, distortion-free photos with your Sigma SA-mount camera. It is equipped with a Super Multi-Layer coating to minimize unnecessary lens flare and ghosting. The inbuilt HSM (Hyper Sonic Motor), which makes use of an optimized AF algorithm, allows you to focus on your subjects with precision and smoothness. The rounded 9-blade diaphragm helps in providing your pictures with an amazing bokeh background effect. The rubber sealing prevents dust and water from seeping into the lens’ mount. Moreover, the lens has an oil- and water-repellent coating on the lens’ rear and front elements.