This full-frame optic was the first full-frame 20mm prime ever built with an F1.4 aperture, making it one of the most desirable lenses on the market for astrophotography, weddings and interiors. Not only does the lens allow four times the amount of light on the sensor than an F2.8 lens with the same ISO and shutter speed, but the wide-aperture also creates a very shallow depth-of-field for pronounced subject separation when shooting portraits or closer-up objects.
Thanks to its advanced optical, which includes 5 SLD, 2 FLD and 2 aspherical elements, the lens has exceptional resolving power, delivering highly-detailed images with excellent sharpness and accuracy from the centre to the periphery of the frame. There is also very well-controlled coma flare, vignetting, distortion and chromatic aberration, ensuring a near-perfect image straight out of camera.
The exceptional build quality of the 20mm F1.4 DG HSM is exactly as you’d expect from an Art-line lens, both in the materials used, the overall ergonomics and the quality of craftsmanship.
The exterior barrel is made of a polycarbonate called Thermally Stable Composite (TSC). Not only is this very strong and light, but it has a similar thermal expansion rate to aluminium. This ensures that the interior aluminium parts and the exterior TSC parts behave in a uniform way as temperatures change.
The focus ring is rubberised for easier operation and focusing is internal, meaning the lens never changes length. This makes it ideal for use on a gimbal as the centre of gravity remains fairly constant.
To reduce flare and ghosting in bright sun, and to help protect the front element from damage if dropped, the lens has a robust fixed petal-type lens hood.
The durable brass mount is surrounded by a rubber seal to help keep out dust and moisture.
Precision brass mount with seal
Protects against dust and moisture.
Made from a strong and light polycarbonate that behaves in a similar way to aluminium.
The 20mm F1.4 DG HSM | Art delivers outstanding optical quality, with excellent rendering of detail right into the corners even wide open at F1.4.
The lens has an advanced optical design made up of 15 elements in 11 groups, including 2 aspherical elements, 5 SLD elements and 2 FLD elements. This ensures razor-sharp results and helps to eliminate chromatic aberration, flare, distortion and vignetting.
Advanced optical coatings reduce flare and ghosting when working in bright direct sunlight, creating high-contrast images with excellent colour saturation and strong blacks.
The wide angle-of-view of the 20mm F1.4 combined with its superb image quality makes this optic a perfect landscape lens. Colours are rich and accurate, and the high resolution optics are able to render an outstanding degree of detail even on the highest resolution cameras.
SIGMA’s two widest-angle Art primes for DSLRs both have extremely fast apertures, which makes them excellent choices for nightscapes and interiors. The 14mm F1.8 offers a wider angle-of-view, but its maximum aperture is two thirds of a stop less wide than the F1.4 of the 20mm. This means it lets in 58% less light wide open. The two lenses are almost exactly the same length, but the 14mm is wider and heavier.
All Sigma cameras and lenses are designed, manufactured and assembled at our sole factory at Aizu in Japan. This domestic production model is unusual in today’s industry, with most imaging companies opting to outsource to other countries to reduce costs. But SIGMA believes that keeping virtually all manufacturing, processing and assembly in Aizu is essential for creating innovative, carefully thought-out and impeccably constructed products that meet the high standards demanded by professional photographers and film-makers around the world.
Sigma chose Aizu as its main production base in the early 1970s. Situated at the base of Mount Bandai in the Fukushima Prefecture, about four hours’ drive north of Tokyo, Aizu has an abundance of very clean water from mountain streams, which is essential for grinding and polishing lenses. Sigma’s founder, Michihiro Yamaki, was also drawn to this area for its workforce, who have a reputation for their craftsmanship, work ethic and attention to detail. Mr Yamaki’s son, Kazuto Yamaki, now the owner and CEO of SIGMA Corporation, has the same unwavering commitment to keeping production in Japan.
Today Sigma’s factory is more than 50,000 square feet in size, and packed full of some of the most advanced optical manufacturing technology in existence. So when you buy a Sigma camera or lens you can be sure that virtually every single component part has been manufactured and assembled by SIGMA, in Japan, with the greatest level of care and attention. We hope you enjoy using our products.
If you want to see how a particular SIGMA lens or camera performs, why not test drive it with our SIGMA Select hire service. Available for selected SIGMA lenses, short-term loans are free of charge (including shipping), with a small fee if you want to test it for longer. Refundable deposit required. Subject to availability.
15 elements in 11 groups
Angle of view
Number of diaphragm blades
9 (rounded diaphragm)
Minimum focusing distance
Maximum magnification ratio
Dimensions (diameter x length)
ø90.7mm × 129.8mm
Corresponding AF mounts
Canon EF | Nikon F | Sigma SA | L-Mount | Sony E
Canon EF barcode
Nikon F barcode
Sigma SA barcode
Sony E barcode
Specifications are for Sigma SA mount
A special coating applied to the front element to help repel water and oil.
This suppresses flare and ghosting by minimising reflections within the lens, ensuring punchy, high-contrast results. All lenses in the current Sigma range feature this technology.
Internal focus or an inner focus system means the lens configuration uses movable internal lens elements that adjust focus without changing the length of the lens barrel. This helps keep the centre of gravity of the lens more constant when changing focus.
Sigma’s Hypersonic Motor (HSM) uses ultrasonic waves to drive the autofocus mechanism. It is extremely quiet, fast and accurate, so is well suited to a wide range of photo and video applications.
The lens has an image circle large enough to be used on a full-frame camera. It can also be used on cameras with a smaller ‘crop’ sensor, provided the mount is compatible.
The mount is the part of the lens that attaches to the camera body. A coated brass mount is used for strength, and is surrounded by a rubber seal to keep out dust and moisture.
This switch toggles between autofocus and manual focus.
The diaphragm is constructed of nine rounded blades for a circular aperture opening and round out-of-focus highlights.