Sigma constant f/3.5 ultra-wide for Canon APS-C with HSM, brighter than variable alternative at mid-range pricing.
The Sigma 10-20mm f/3.5 DC HSM is the faster-aperture version of Sigma's APS-C ultra-wide zoom — a constant f/3.5 across the zoom range. Canon EF mount.
10-20mm focal length. f/3.5 constant maximum aperture. HSM autofocus motor. DC = APS-C coverage. 82mm filter thread. Canon EF mount.
The f/3.5 version provides constant f/3.5 across the full zoom range — a meaningful improvement over the f/4-5.6 variant (id 3194) for low-light ultra-wide photography. HSM provides fast AF. A step up in both aperture and price from the f/4-5.6.
On the used market the Sigma 10-20mm f/3.5 DC HSM is the faster ultra-wide for Canon APS-C. Condition checks: constant f/3.5 aperture, HSM motor. Canon EF mount.