The Sigma 20mm f/1.4 DG DN Art is an ultrawide prime lens designed for Sony E-mount mirrorless cameras. It delivers outstanding corner-to-corner sharpness and a fast f/1.4 aperture, making it a top choice for low-light shooting and astrophotography. In addition, new features make it especially reliable under dark skies.
Optical Performance
Sigma combined advanced optics with in-camera corrections to minimize distortion. Two SLD and three aspherical elements reduce chromatic aberrations and enhance clarity. A concave double-sided aspherical element improves edge-to-edge sharpness. Moreover, the Super Multilayer Coating reduces flare and ghosting, even in backlit conditions.
Astrophotography Features
This lens was carefully optimized for astrophotography. It controls sagittal coma flare, delivering sharp, pin-point stars across the frame. A new Manual Focus Lock (MFL) switch disables the focus ring, ensuring the set focus remains unchanged during long exposures. The design also accepts 82mm front filters, a rare option for ultrawide primes, and supports rear sheet filters for creative effects.
Build and Handling
The lens includes a smooth aperture ring with both a click switch and a lock switch, preventing accidental changes. Its rounded 11-blade diaphragm creates beautiful background blur. A petal-shaped hood reduces flare and protects the front element. Additionally, a curved lip at the front secures an optional lens heater, useful during astrophotography sessions.
Autofocus and Precision
The inner focus system uses a precise STM stepping motor for fast, quiet, and accurate autofocus. It also supports Sony’s AF Assist function on select models. The brass bayonet mount ensures durability and long-term precision.
