Sigma Corporation (株式会社シグマ,Kabushiki-gaisha Shiguma) is a Japanesecompany, 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 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 SAlens 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 will be 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.
Sigma has made a number of film SLR cameras, including the SA-300, SA-5, SA-7 and SA-9. Their latest consumer digital SLR is the SD15. During photokina 2010, Sigma announced a new flagship DSLR camera, the SD1. SD1 features a new 46MP Foveon X3 sensor with 1.5x crop, as opposed to the 1.7x crop of previous models.
Sigma also produces the DP series of high-end compact digital cameras. The FoveonAPS-C sized sensors are similar to those used in the DSLR line. The current line makes use of the Quattro sensor, a variant of the Foveon design that has a higher resolution top layer and lower resolution lower layers combined into a final image that is claimed to be equivalent to a 39 megapixel color filter array image. The four compact cameras are differentiated by their fixed prime lens, with the ultra wide DP0, the wide DP1, the normal DP2 and the telephoto DP3.
In February 2016, Sigma announced two new mirrorless cameras—the SD Quattro and SD Quattro H. Both cameras use the full-depth Sigma SA mount, allowing the use of existing SA-mount lenses, and also use Foveon Quattro sensors. The SD Quattro uses an APS-C sensor with 19.6 MP in the top layer, while the SD Quattro H uses an APS-H (1.35x crop) sensor with 25.5 MP in the top layer. The company claims that the Foveon Quattro technology produces a level of detail equivalent to that of a Bayer sensor with twice the pixel count.
In August 2013, Sigma announced that starting the following month, it would offer a mount conversion service for its newest "Global Vision" lenses—those with either an "A" (Art), "C" (Contemporary), or "S" (Sport) as part of their model name. For a cost that varies with lens and market—from $80 to $250 in the U.S., not including shipping costs—owners can send their lenses to their local Sigma company, which in turn sends them to Japan for mount replacement, including calibration and optimization for the new camera system. Lenses designed for DSLRs can be converted to Canon EF, Nikon F, Pentax K, Sigma SA, or Sony A mounts; those designed for MILCs can be converted to Micro Four Thirds or Sony E-mount.
APO — Apochromatic lens element(s), originally for "Advanced Performance Optics", not necessarily apochromatic
OS — In-lens "Optical Stabilization", analogous to Nikon VR or Canon IS
HSM — "Hyper-Sonic Motor", either in-lens ultrasonic motor or micro-motor, analogous to Nikon SWM (AF-S) (ultra-sonic or micro-motor), Canon USM (ultrasonic or micro-motor), Minolta/Konica Minolta/Sony SSM (ultrasonic motor) or Sony SAM (micro-motor), etc.
A — "Art Series", large aperture prime and zoom lenses, high optical performance. USB dock compatible. Part of 2013 lens lineup restructuring.
C — "Contemporary Series", combining optical performance with compactness. USB dock compatible. Part of 2013 lens lineup restructuring.
S — "Sports Series", telephoto and super-telephoto lenses. USB dock compatible. Part of 2013 lens lineup restructuring.
EX — "Excellence", EX-finish, high performance series.
DG — "Digital Grade", coatings optimized for DSLRs, full-frame as well as APS-C, also usable on 35mm film SLRs
Sigma macro, telephoto and wide angle lenses (left to right)
DC — "Digital Compact", lenses for DSLRs featuring APS-C size sensors, only
DF — "Dual Focus", lens features clutch to disengage focus ring when in AF mode
FLD — "'F' Low Dispersion" glass, the highest level low dispersion glass available with extremely high light transmission. This glass has a performance equal to fluorite glass which has a low refractive index and low dispersion compared to current optical glass
HF — "Helical Focusing", front element of lens does not rotate (useful for polarizing filters and petal lens hoods)
RF — "Rear Focusing", lenses employing rear-focusing, no length changes during focussing, no rotating front elements
IF — "Inner Focusing", length of lens does not change during focusing, no rotating front elements
In 2011, Nikon filed a suit against Sigma, alleging it had violated patents relating to Nikon's "Vibration Reduction" image stabilisation technology. In 2015, the suit ended through settlement, with no details disclosed.