Sigma 17-50mm f/2.8 EX DC OS HSM Lens for Nikon F

The Sigma 17-50mm f/2.8 EX DC OS HSM is a third-party APS-C format standard zoom lens designed for Nikon F-mount crop-sensor DSLRs, offering a constant f/2.8 maximum aperture across its focal range as an alternative to first-party options at a more accessible price point. The focal range translates to approximately 25.5-75mm full-frame equivalent on APS-C bodies, covering wide-angle through short telephoto in a single lens. Optical Stabilization (OS) provides shake compensation for handheld shooting, and the Hyper Sonic Motor (HSM) delivers fast, quiet autofocus with full-time manual focus override. The optical construction includes Special Low Dispersion (SLD) and aspherical elements to control chromatic aberration and distortion throughout the zoom range. The EX designation indicates Sigma’s higher-grade build quality with a finish resistant to everyday handling demands.

– Mount: Nikon F (APS-C/DX only)
– Focal Length: 17-50mm (approx. 25.5-75mm full-frame equivalent on APS-C)
– Maximum Aperture: f/2.8 (constant)
– Image Stabilization: Optical Stabilization (OS)
– Autofocus: Hyper Sonic Motor (HSM) with full-time manual focus override
– Optical Construction: Includes SLD and aspherical elements
– Filter Thread: 77mm
– Build: EX-grade construction
– Compatible Format: APS-C/DX F-mount bodies only