Sigma Corporation is a Japanese corporation which manufactures a range of photographic lenses and their own proprietary camera systems. Many of these lenses are also available for popular mounts including Nikon, Canon, and Sony. The list is not comprehensive though as there are other mounts as well which Sigma’s lenses are compatible with.
They have a dedicated line of mirrorless lenses as well for Panasonic, Olympus and Sony cameras. They are an extremely popular option for high-quality third-party lenses for other big brand OEM cameras.
Apart from photographic lenses, Sigma also manufactures a range of cine lenses, teleconverters, flashes, lens accessories, and flash accessories. Sigma was founded back in 1961 by Michihiro Yamaki. For a time Sigma manufactured a range of film SLR cameras. Some of the best in the business. Sigma also has a highly advanced range of compact system cameras – the DP series.