Compare lenses

Canon RF 28-70mm f/2L USM vs Sigma 17-40mm f/1.8 DC Art

The Canon RF 28-70mm f/2L USM and the Sigma 17-40mm f/1.8 DC Art side by side, computed from this guide's catalogue.

Which to pick

Pick the Canon RF 28-70mm f/2L USM if you want more reach (to 70mm equivalent) and coverage of full frame, so it suits the larger-sensor bodies too. Pick the Sigma 17-40mm f/1.8 DC Art if you want a brighter f/1.8 (0.3 stops more light), for dim light and softer backgrounds; 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 (525 g against 1430 g).

Still torn? Ask the guide about the Canon RF 28-70mm f/2L USM and the Sigma 17-40mm f/1.8 DC Art

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 28-70mm f/2L USM	Sigma 17-40mm f/1.8 DC Art
Maker	Canon	Sigma
Focal length	28-70mm (zoom)	17-40mm (zoom)
Full-frame equivalent	28-70mm	26-60mm on APS-C
Maximum aperture	f/2	f/1.8brighter
Made for	Full frame	APS-C
Mounts	Canon RF	Sony E, Fujifilm X, L-Mount, Canon RF
Stabilised	no	no
Autofocus	yes	yes
Zoom range	2.5×	2.4×
Weight	1430 g	525 glighter
Cameras it fits	18 in this guide	115 in this guidefits more cameras

Focal range, in full-frame terms

Canon RF 28-70mm f/2L USM: 28-70mm.

Sigma 17-40mm f/1.8 DC Art: 17-40mm on APS-C, like 26-60mm.

Aperture

Canon RF 28-70mm f/2L USM: f/2 wide open.

Sigma 17-40mm f/1.8 DC Art: f/1.8 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 28-70mm f/2L USM fits 18 and the Sigma 17-40mm f/1.8 DC Art 115.