Standard lens"" that matches the optical performance standards set by the Sigma Contemporary line of lenses.Sigma I series lenses are developed around the concept of ""Compact everyday lenses with outstanding image quality"" and the Sigma 50mm F2 Dg | Contemporary is exactly that. It features high-quality optics in a compact size, perfect for a wide variety of photographic styles. Built from the ground up for mirrorless cameras, the Sigma 50mm F2 Dg | Contemporary is constructed using a single Sld glass element and three aspherical lens elements that are excellent at correcting various types of aberration for clear, high-definition images.The conflicting ideals of improving optical performance while reducing body size and weight are achieved through the latest optical design, and the processing and production technologies at Sigma's only production facility in Aizu.The 50mm focal length is mostly known for portrait photography, so careful consideration was taken when designing the lens, focusing on the smoothness of the bokeh created by the F2 aperture. Its optical design gives smooth transitions from in-focus to out-of-focus areas, and helps minimize flare and ghosting caused by backlit environments. The quiet stepping motor provides quick, reliable autofocusing for both stills and video.Expanding the I series lineup. ""Creating pictures that are beyond beautiful"".The 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 photographers looking for something more than something that simply captures images when they choose to own a camera and lens, 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.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 lineup for professional cinematographers and provide a tactile, ergonomic feel that make the lens a pleasure to use.a smooth hairline cover ring is used between the focus and aperture rings to act as a finger hold when attaching and detaching the lens.Magnetic metal lens capI series lenses are accompanied by a dedicated magnetic metal lens cap, in addition to a normal plastic cap. This dedicated metal cap clips to the front surface of the lens magnetically.