Sigma 20mm F1.8 EX DG Aspherical RF

Focal length: 20 mm
Aperture: f/1.8
Weight: 520 g
Filter diameter: 82 mm
Min. focus distance: 20 cm
Length: 89.5 mm

At a Glance

This prime brings a 20 mm ultra-wide view at f/1.8 to Nikon F-mount full-frame cameras. The 20 cm minimum focus distance gives a magnification of 0.25x. It suits landscape, architecture, interiors and night sky.

Good for

Landscape
Architecture
Interiors
Night sky

Derived from the manufacturer data, not from our own tests. How we check

Technical Specifications

Min. focal length: 20 mm
Max. focal length: 20 mm
Max. aperture (min. zoom): f/1.8
Max. aperture (max. zoom): f/1.8
Min. aperture: f/22
Elements: 13
Groups: 11
Weight: 520 g (1.15 lb)
Filter diameter: 82 mm
Min. focus distance: 20 cm (7.87 in)
Max. magnification: 1:4 (0.25×)
Length: 89.5 mm (3.52 in)
Diameter: 88.6 mm (3.49 in)

Manufacturer data: sigma-global.com

Last checked: October 13, 2026 (against the manufacturer data) · How we check

Simulate depth of field and angle of view

Compare with other lenses

Which cameras does the Sigma 20mm F1.8 EX DG Aspherical RF fit?

The Sigma 20mm F1.8 EX DG Aspherical RF is a full-frame lens for Nikon F-Mount cameras. On full-frame bodies it uses the whole sensor; on APS-C Nikon F-Mount cameras its field of view equals 30 mm in full-frame terms.

Nikon F-Mount cameras

Full frame:: Nikon D6,Nikon D780,Nikon D850,Nikon D5,Nikon D810A,Nikon D4S,Nikon D810,Nikon D750,Nikon Df,Nikon D610,Nikon D4,Nikon D800,Nikon D800E,Nikon D600,Nikon D3S,Nikon D3X,Nikon D700
APS-C:: Nikon D3500,Nikon D7500,Nikon D500,Nikon D3400,Nikon D5600,Nikon D5500,Nikon D7200,Nikon D3300,Nikon D7100,Nikon D5300,Nikon D3200,Nikon D5200,Nikon D5100,Nikon D7000,Nikon D3100,Nikon D300S,Nikon D5000,Nikon D3000,Nikon D90,Nikon D60

With the Nikon FTZ II / FTZ the lens can also be used on Nikon Z (DX/FX) cameras.