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Sigma 20mm F1.8 EX DG Aspherical RF

Canon EF Autofocus

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
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At a Glance

This 20 mm ultra-wide prime for full-frame Canon EF opens to f/1.8. From 20 cm it reaches 0.25x magnification, which is notably close for a wide-angle. Landscape, architecture, interiors and night sky are fitting subjects.

Good for

  • Landscape
  • Architecture
  • Interiors
  • Night sky

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

Technical Specifications

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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 Canon EF cameras. On full-frame bodies it uses the whole sensor; on APS-C Canon EF cameras its field of view equals 32 mm in full-frame terms.

Canon EF cameras

Full frame:
Canon EOS-1D X Mark III,Canon EOS 6D Mark II,Canon EOS-1D X Mark II,Canon EOS 5D Mark IV,Canon EOS 5Ds,Canon EOS 5Ds R,Canon EOS 5D Mark III,Canon EOS 6D,Canon EOS-1D C,Canon EOS-1D X,Canon EOS 5D Mark II
APS-C:
Canon EOS 850D (Rebel T8i),Canon EOS 90D,Canon EOS 250D (Rebel SL3),Canon EOS 4000D (3000D, Rebel T100),Canon EOS 2000D (1500D, Rebel T7),Canon EOS 800D (Rebel T7i),Canon EOS 77D,Canon EOS 200D (Rebel SL2),Canon EOS 80D,Canon EOS 1300D (Rebel T6),Canon EOS 750D (Rebel T6i),Canon EOS 760D (Rebel T6s),Canon EOS 7D Mark II,Canon EOS 1200D (Rebel T5),Canon EOS 70D,Canon EOS 700D (Rebel T5i),Canon EOS 100D (Rebel SL1),Canon EOS 650D (Rebel T4i),Canon EOS 60Da,Canon EOS 600D (Rebel T3i),Canon EOS 1100D (Rebel T3),Canon EOS 550D (Rebel T2i),Canon EOS 60D,Canon EOS 7D,Canon EOS 500D (Rebel T1i),Canon EOS 50D,Canon EOS 450D (Rebel XSi),Canon EOS 1000D (Rebel XS)

With the Canon Mount Adapter EF-EOS R the lens can also be used on Canon RF cameras.

With the Canon Mount Adapter EF-EOS M the lens can also be used on Canon EF-M cameras.

Sigma 20mm F1.8 EX DG Aspherical RF compared

Key specs side by side with the most similar Canon EF lenses.

LensSigma 20mm F1.8 EX DG Aspherical RFSigma 20mm F1.4 DG HSM ArtSamyang / Rokinon 20mm F1.8 ED AS UMCCanon EF 20mm f/2.8 USM
Focal length20 mm20 mm20 mm20 mm
Max. aperturef/1.8f/1.4f/1.8f/2.8
Weight520 g950 g497 g405 g
Filter diameter82 mm–77 mm72 mm
Min. focus distance20 cm28 cm20 cm25 cm
Length89.5 mm130 mm88.4 mm71 mm
Autofocusyesyesnoyes
Image stabilizationnononono
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Sigma 20mm F1.8 EX DG Aspherical RF: FAQ

Does the Sigma 20mm F1.8 EX DG Aspherical RF have autofocus?

Yes, the Sigma 20mm F1.8 EX DG Aspherical RF has autofocus.

Does the Sigma 20mm F1.8 EX DG Aspherical RF have image stabilization?

No, the Sigma 20mm F1.8 EX DG Aspherical RF has no stabilization of its own. On cameras with in-body image stabilization (IBIS) the image is still stabilized.

How much does the Sigma 20mm F1.8 EX DG Aspherical RF weigh?

The Sigma 20mm F1.8 EX DG Aspherical RF weighs 520 g. It is 89.5 mm long with a diameter of 88.6 mm.

What filter size does the Sigma 20mm F1.8 EX DG Aspherical RF use?

The Sigma 20mm F1.8 EX DG Aspherical RF takes 82 mm screw-in filters.

How close can the Sigma 20mm F1.8 EX DG Aspherical RF focus?

The minimum focus distance of the Sigma 20mm F1.8 EX DG Aspherical RF is 20 cm, measured from the sensor plane.

Is the Sigma 20mm F1.8 EX DG Aspherical RF a full-frame lens?

Yes, the Sigma 20mm F1.8 EX DG Aspherical RF covers full frame. On APS-C cameras its field of view equals 32 mm in full-frame terms.

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