Canon RF 28-70mm f/2 L USM vs Sigma 17-40mm f/1.8 DC Art
Both are Canon RF mount zooms for pro standard zoom and low-light — here's how the specs differ and which to pick. Every spec is from the manufacturer's own catalog.
| Spec | Canon RF 28-70mm f/2 L USM | Sigma 17-40mm f/1.8 DC Art |
|---|---|---|
| Focal length | 28-70mm | 17-40mm |
| Max aperture | f/2 | f/1.8 |
| Type | zoom | zoom |
| Coverage | full-frame | APS-C |
| Mount | Canon RF | Canon RF |
Which should you buy?
- the Sigma 17-40mm f/1.8 DC Art opens wider (f/1.8) — brighter in low light and more background blur
- the Canon RF 28-70mm f/2 L USM covers 28-70mm and the Sigma 17-40mm f/1.8 DC Art covers 17-40mm — pick the range that matches what you shoot
- the Canon RF 28-70mm f/2 L USM covers full-frame (also works on APS-C bodies); the Sigma 17-40mm f/1.8 DC Art is APS-C-only — it won't fill a full-frame sensor
- the Canon RF 28-70mm f/2 L USM is first-party (Canon) for guaranteed full autofocus and in-camera corrections; the Sigma 17-40mm f/1.8 DC Art is third-party — usually the value pick
Where to buy
Canon RF 28-70mm f/2 L USMSee price on Amazon
Sigma 17-40mm f/1.8 DC ArtSee price on Amazon
FAQ
What's the difference between the Canon RF 28-70mm f/2 L USM and the Sigma 17-40mm f/1.8 DC Art?
The Canon RF 28-70mm f/2 L USM is 28-70mm f/2 zoom, full-frame; the Sigma 17-40mm f/1.8 DC Art is 17-40mm f/1.8 zoom, APS-C. Both fit the Canon RF mount.
Which is better in low light, the Canon RF 28-70mm f/2 L USM or the Sigma 17-40mm f/1.8 DC Art?
The Sigma 17-40mm f/1.8 DC Art — its f/1.8 maximum aperture lets in more light and gives more background blur than the f/2 of the other.
Do the Canon RF 28-70mm f/2 L USM and Sigma 17-40mm f/1.8 DC Art fit the same camera?
Yes — both are Canon RF mount lenses, so they fit Canon EOS R series (full-frame R5/R6/R8) and APS-C (R7/R10/R50). Note the Sigma 17-40mm f/1.8 DC Art is APS-C-only and won't fill a full-frame sensor.
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