Sigma Corporation (株式会社シグマ, Kabushiki-gaisha Shiguma) is a Japanese company, manufacturing cameras, lenses, flashes, and other photographic accessories. All Sigma products are produced in the company's own Aizu factory in Bandai, Fukushima, Japan. Although Sigma produces several camera models, the company is best known for producing high-quality lenses and other accessories that are compatible with the cameras produced by other companies.
The company was founded in 1961 by Michihiro Yamaki, who was Sigma's CEO until his death at age 78 in 2012.
Sigma products work with cameras from Canon, Nikon, Pentax, Sony, Olympus, and Panasonic, as well as their own cameras.
Sigma has also made lenses under the Quantaray name, which have been sold exclusively by Ritz Camera. Similarly, Sigma lenses were sold exclusively by the former Wolf Camera, but following the merger of Wolf and Ritz, both brands can be purchased.
Sigma's digital SLRs, the SD9, SD10, SD14, and SD15, plus the latest SD1 are unusual in their use of the Foveon X3 image sensor. The company's mirrorless cameras, the Sigma SD Quattro and SD Quattro H use the Foveon Quattro sensor, an updated version of the Foveon X3. All use the SA lens mount. The Sigma DP series of high-end compact P&S cameras also use the Foveon Quattro sensor, which gives them a much larger sensor than other cameras of this type.
In September 2018 Sigma became one of the founding members of the L-Mount Alliance; it announced that it will cease to develop SA-mount cameras and instead use Leica's L-Mount. A new full-frame mirrorless camera, Sigma FP, was launched in 2019 along with a range of L-Mount lenses and adapters.
Sigma is the world's largest independent lens manufacturer and is a family-owned business.