10–20mm · f/4–5.6
The Sigma 10-20mm F4-5.6 EX DC HSM is an affordable ultra-wide zoom for APS-C DSLRs, offering a useful 10mm wide end. Optically, it delivers decent sharpness with good control of chromatic aberration, but suffers from significant curvature of field, inconsistent sharpness, and notable distortion. Build quality is solid with Sigma's EX construction, and the HSM autofocus is fast and quiet. It suits landscape and indoor photographers on a budget who prioritize wide angles over ultimate sharpness.