The Sigma 24mm 1.4 DG HSM Art is a state of the art wide-angle prime lens designed for Full Frame cameras but will work with APS-C sensors as well. Using over 50 years of lens making experience, particularly the knowledge gained from the 35mm 1.4 Art and the 50mm 1.4 Art, the 24mm 1.4 Art is aimed at being the new standard for fast aperture wide angle prime lenses. The latest optical design allows for the utmost in image quality with careful attention paid to edge to edge performance. An optimized power layout places the aspherical lens elements in the rear and adjusts the incidence angle of light source allowing for great performance wide open. Using premium FLD & SLD glass elements, the lens brings aberrations and distortion to a minimum, an issue many wide-angle lenses suffer from. With class leading performance, this lens is ideal for wedding photography, landscape photography, videography, astrophotography, lowlight/indoor photography and event photography. As with all Global Vision lines, the 24mm will be tested using the proprietary ?A1? measuring system ensuring the highest standard of operation. The Sigma 24mm Art is compatible with the USB dock to update and customize and is also compatible with the Mount Conversion Service. A staple procedure for the Global Vision lines, every lens will be tested using the proprietary ?A1? measuring system. SPECIFICATIONS Lens Construction 15 elements in 11 groups Angle of View (35mm) 84.1? Number of Diaphragm Blades 9 (Rounded diaphragm) Minimum Aperture F16 Minimum Focusing Distance 25 cm / 9.8 in. Filter Size (mm) ?77? Maximum Magnifications 1?5.3 Dimensions(Diameter x Length) ?85mm x 90.2mm / 3.3 in. x 3.6 in. Weight 665 g / 23.5 oz.