The SIGMA 20mm F1.4 DG DN | Art is a wide-angle, ultra-wide-aperture prime that is perfect for
astrophotography. Available in L-Mount and Sony E-mount, it delivers outstanding Art-line optical
quality and offers a range of advanced features. As well as being very well-suited to Astro, the 20mm F1.4 is an ideal optic for landscapes, interiors and a range of other wide-angle applications.
Weighing in at just 635g, the lens is significantly lighter and more portable than Sigma’s existing 20mm F1.4, and introduces a number of important features including a manual aperture ring with de-click and lock functionality, a front filter thread and rear filter holder, a Lens Heater Retainer to hold a heat strip in position, and an all-new Manual Focus Lock switch to fully deactivate the focus ring.
The optical performance of the lens is exceptional, with ultra-sharp results across the entire frame even at F1.4, and very well controlled sagittal coma flare – essential for astrophotography. The bright aperture is perfect for night sky landscapes, as well as for hand-held low-light shooting and for achieving a shallow depth-of-field.
This superb image quality, compact form-factor and advanced feature-set, combined with a beautifully constructed body, make for a versatile, high-performance optic that will enable photographers to unleash their creative potential and start achieving wide-angle images with impact.
* Figures are for L-Mount
Key Features:
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.
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 Astro-photographers, who may want to attach a 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 to hold the focus
ring in position, are over.
Another brand-new feature designed with Astro-photographers 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 customized*1 to a range of different functions.
*1 Only on compatible cameras. Available functions may vary depending on the camera used.
Additional Features:
Lens construction: 17 elements in 15 groups, with 2 FLD and 3 aspherical elements
Internal focus system
Compatible with high-speed autofocus
Stepping Motor
Compatible with Lens Aberration Correction
Function available on supported cameras only. Available corrections and auto correction functionality may vary depending on the camera model.
On cameras where lens aberration correction is controlled with ‘ON’ or ‘OFF’ in the camera menu, please set all aberration correction functions to ‘ON’ (AUTO).
Support for DMF and AF+MF
Compatible with AF Assist (Sony E-mount only)
Super Multi-Layer Coating
Nano Porous Coating
Water- and oil-repellent coating
Focus Mode Switch
Lens Heater Retainer
Aperture Ring
Aperture Ring De-click Switch
Aperture Ring Lock Switch
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
9-blade rounded diaphragm
High-precision, durable brass bayonet mount
Every single lens is evaluated with Sigma’s proprietary MTF measuring system
Key Specifications: (The figures below are for L-Mount)
Lens construction: 15 groups, 17 elements (2 FLD and 3 aspherical elements)
Angle-of-view: 94.5°
Number of diaphragm blades: 11 (rounded diaphragm)
Minimum aperture: F16
Minimum focusing distance: 23cm
Maximum magnification rat/span>
Filter size: f82mm
Dimensions (max diameter x length): f87.8mm x 111.2mm
Weight: 635g
