A Hyper Sonic Motor (HSM) ensures quiet, smooth and accurate autofocusing and paired with Special Low Dispersion (SLD) glass and Super Multi-Layer coating, the 50mm 1., 4 is a high performance lens for modern DSLR sensors. A Hyper Sonic Motor (HSM) ensures quiet, smooth and accurate autofocusing and paired with Special Low Dispersion (SLD) glass and Super Multi-Layer coating, the 50mm 1., 4 is a high performance lens for modern DSLR sensors , Sigma 50mm 1., 4 DG HSM has been redesigned and reengineered to set a new standard for the Art line^With a large 1., 4 aperture, the Sigma 50mm 1., 4 prime lens is pro level performer for shooting everything including portrait photography, landscape photography, studio photography and street photography^A Hyper Sonic Motor (HSM) ensures quiet, smooth and accurate autofocusing and paired with Special Low Dispersion (SLD) glass and Super Multi-Layer coating, the 50mm 1., 4 is a high performance lens for modern DSLR sensors The Sigma 50mm f/1.4 Art features a 77mm filter thread, which makes it easy to use common clear, polarizing and ND filters without having to... High resolution and high performance 50mm focal length prime lens with a large f1.4 maximum aperture. Suitable for both 35mm, full frame and APS-C sized... ca Product Description 50mm F1., 4 DG HSM ART- redesigned and reengineered to set a new standard for the Art line. From the Manufacturer 50mm F1., 4 DG HSM ART- redesigned and reengineered to set a new standard for the Art line. How to get the best results from the Sigma 50mm 1.4 Art lens Sigma 50mm 1.4 Sigma 50mm F/1.4 DG HSM Art Lens - Camera News At Sigma 50mm F1.4 Lens