Premium Compact Primes"" for mirrorless usersThe Sigma I series features full-frame compatible lenses that offer new value to mirrorless systems. The combination of superb optical performance with a level of compactness that is perfectly suited to smaller and lighter modern mirrorless cameras will bring you new opportunities for a perfect shot. Sigma is aware that in today's world we have a wide range of camera choices, especially with the increase in mobile phone ownership.But with many people look for something more than a mere act of ""taking pictures"" when they choose to own a camera and lenses, I series lenses offer the ultimate combination of superb optical performance, outstanding usability and compact form-factor. Sigma's excellence in development and production technologies has been built up since our founding in 1961 and became increasingly sophisticated with the introduction of the Sigma Global Vision brand in 2012. With this as a base, Sigma has given careful thought to the quality of the products, the feeling of using it and the pleasure of owning it. This is how the I series was born.New standards of optical performance for the Contemporary lineThe Sigma 24mm F2 Dg | Contemporary combines the highest level of optical performance even at its maximum aperture of F2 and a well-balanced body.The lens uses two Sld glass elements and one Fld glass element to correct axial chromatic aberration, which is a particular concern with bright lenses. It also incorporates two high-precision glass-molded aspherical elements, made possible by the processing technology of Sigma's sole production facility in Aizu. This has enabled the total number of lens elements to be kept down and the size and weight of the lens to be reduced, while providing excellent correction of various aberrations.In anticipation of wide-angle lens applications, Sigma's optical designers have ensured the lens resolution is extremely high, and is uniform from the center to the periphery of the image. Sagittal coma flare is also well suppressed, giving the lens a high degree of rendering power that makes it ideal for night sky photography.The Af drive system incorporates a quiet, high-speed stepping motor. This allows photographers to capture every detail of the spacious 24mm scene with precise Af.Use of multiple high-precision aspherical glass molded lensesThe surface of molds for glass molding, which is a process that forms optical components by pressing glass materials at high temperatures, requires ultra-high precision. Sigma uses high-precision molds whose surfaces are controlled with an accuracy of +/-5 nanometers (0.000005 mm) or smaller. High precision aspherical glass molded lenses archives both good aberration correction and compact lens size.Exceptional I series build quality with a compact form-factorAll I series lenses have an all-metal construction. The precision-cut aluminum parts not only give the barrel a sleek, stylish finish, but provide superb durability that improves the quality of the entire product. Metal materials are also used in internal structures that slide with the operation ring for added robustness. These high-precision components crafted with Sigma's cutting-edge metalworking technology are also used in Sigma's Cine Lens line-up for professional cinematographers and provide a tactile, ergonomic feel that make the lens a pleasure to use.