Compare lenses

Canon RF 10-20mm f/4L IS STM vs Sigma 10-18mm f/2.8 DC DN Contemporary

The Canon RF 10-20mm f/4L IS STM and the Sigma 10-18mm f/2.8 DC DN Contemporary side by side, computed from this guide's catalogue.

Which to pick

Pick the Canon RF 10-20mm f/4L IS STM if you want optical stabilisation, which helps most on bodies without it; a wider view (from 10mm equivalent); and coverage of full frame, so it suits the larger-sensor bodies too. Pick the Sigma 10-18mm f/2.8 DC DN Contemporary if you want a brighter f/2.8 (1.0 stops more light), for dim light and softer backgrounds; more reach (to 27mm equivalent); a design for APS-C, which usually means smaller and lighter; a fit on more cameras (115 against 18 in this guide); and a lighter lens (255 g against 570 g).

Still torn? Ask the guide about the Canon RF 10-20mm f/4L IS STM and the Sigma 10-18mm f/2.8 DC DN Contemporary

Specs side by side

Rows that differ are in full colour; the better value is marked where one is better by any measure.
Spec	Canon RF 10-20mm f/4L IS STM	Sigma 10-18mm f/2.8 DC DN Contemporary
Maker	Canon	Sigma
Focal length	10-20mm (zoom)	10-18mm (zoom)
Full-frame equivalent	10-20mm	15-27mm on APS-C
Maximum aperture	f/4	f/2.8brighter
Made for	Full frame	APS-C
Mounts	Canon RF	Sony E, Fujifilm X, L-Mount, Canon RF
Stabilised	yesstabilised	no
Autofocus	yes	yes
Zoom range	2.0×	1.8×
Weight	570 g	255 glighter
Cameras it fits	18 in this guide	115 in this guidefits more cameras

Focal range, in full-frame terms

Canon RF 10-20mm f/4L IS STM: 10-20mm.

Sigma 10-18mm f/2.8 DC DN Contemporary: 10-18mm on APS-C, like 15-27mm.

Aperture

Canon RF 10-20mm f/4L IS STM: f/4 wide open.

Sigma 10-18mm f/2.8 DC DN Contemporary: f/2.8 wide open.

Each opening drawn to scale against f/1.4: a smaller f-number lets in more light and blurs the background more.

Field of view

How wide each sees, at each end, on the sensor it was made for.

Cameras they fit

18 cameras in this guide take both, so either works on the same body. In all, the Canon RF 10-20mm f/4L IS STM fits 18 and the Sigma 10-18mm f/2.8 DC DN Contemporary 115.