Sigma AF 20mm F1.4 DG DN | Art  for L-Mount 

Outstanding optical performance

The SIGMA 20mm F1.4 DG DN | Art delivers highly detailed results that easily satisfy the demands of professional photographers and film-makers.

The lens is constructed with 17 elements arranged in 14 groups, including two SLD elements and three aspherical elements, one of which is the largest double-sided aspherical element ever produced by Sigma. This advanced optical design rigorously suppresses a range of optical aberrations, such as sagittal coma flare and chromatic aberration, and ensures pin-sharp results right across the frame even wide-open at F1.4.

The outstanding performance of this all-new wide-angle prime has been made possible thanks to Sigma’s unparalleled manufacturing technology at its sole production base at Aizu in Japan, which has evolved over 60 years of lens development. The company pioneered the world’s first full-frame 20mm F1.4 prime in 2015, and has since produced some of the highest-performing wide-angle primes and zooms on the market, including the 14mm F1.8 DG HSM | Art and the 14-24mm F2.8 DG DN | Art.

Advanced functionality for every shooting situation

SIGMA’s experience in optical design, combined with its high-precision manufacturing capability, has made it possible to equip the 20mm F1.4 DG DN | Art with a front filter thread in spite of its very large F1.4 aperture and ultra-wide angle-of-view. The lens also comes with a rear filter holder, giving photographers the freedom to more easily combine multiple filters. This is particularly useful for astrophotographers, who may want to attach a light pollution filter at the front and a soft filter at the rear. 

The lens has an aperture ring built in, which is de-clickable for a smooth transition between aperture settings – useful for changing exposure seamlessly during video shooting. The aperture ring also has a lock switch. A new Manual Focus Lock (MFL) switch completely deactivates the focus ring, ensuring the focus position won’t change if it is accidentally knocked. So for night-sky photographers, the days of using tape the hold the focus ring in position are over.

Another brand new feature designed with astrophotographers in mind is the Lens Heater Retainer, which is a pronounced lip around the front element to keep a heat strip firmly in place. Heat strips are commonly used to stop condensation forming on the elements when working at night. 

 An AFL button is built into the lens, which can be customised to a range of different functions.

Superb build quality with uncompromising attention to detail

Designed and manufactured at Sigma’s sole factory in Aizu in Japan, the 20mm F1.4 DG DN meets the exceptionally high production standards that users have come to expect from Sigma’s Global Vision lenses.

The robust body is built from a combination of aluminum and Thermally Stable Composite (TSC), giving it a sleek finish, and the focus ring has a smooth, well damped action. A petal-shaped lens hood is included, and equipped with a lock mechanism to keep it securely fastened to the lens. A rubber grip makes it easier to attach and remove the hood.

Built with a dust and splash-resistant structure, a water- and oil-repellent coating on the front element, and a rubber seal around the mount, the 20mm F1.4 DG DN is safe to use during longer outdoor shoots. The 20mm F1.4 DG DN is built with exceptional attention to detail in its functionality, construction and design ergonomics, helping users achieve the best possible results in any shooting situation.

Additional features

• Internal focus system

• Compatible with high-speed autofocus

• Stepping Motor

• Compatible with Lens Aberration Correction

• Support for DMF and AF+MF

• Compatible with AF Assist (Sony E-mount only)

• AFL Button

• MFL Switch

• Rear filter holder

• Petal-type lens hood (LH878-04)

• Mount with dust and splash-resistant structure

• Support for switching between linear and non-linear focus ring settings (L-Mount only)

• Compatible with SIGMA USB DOCK UD-11 (sold separately; L-Mount only)

• Designed to minimise flare and ghosting

• Aperture Ring

• Aperture Ring De-click Switch

• 9-blade rounded diaphragm

• Every single lens is evaluated with Sigma’s proprietary MTF measuring system