Sigma EX ultra-wide zoom for Nikon F mount with aspherical elements and f/2.8 wide end.
The Sigma 17-35mm f/2.8-4 D EX Aspherical is a wide-angle zoom for Nikon F mount, covering a useful ultra-wide to moderate wide-angle range. The EX designation indicates Sigma's premium build tier, with aspherical elements to control distortion and aberrations across the zoom range for improved image quality.
Optical quality is good with sharp centre performance and reasonable edge sharpness, particularly at moderate apertures. The f/2.8 wide end provides useful speed for the widest settings, though the aperture narrows to f/4 at the 35mm end. The aspherical elements help control the distortion common in ultra-wide zoom designs.
Build quality follows the EX standard with a metal barrel and rubber zoom and focus rings. The lens is compact for a full-frame ultra-wide zoom and balances well on Nikon bodies. The D designation indicates distance information communication with the camera for improved metering with Nikon bodies.
On the used market, the Sigma 17-35mm f/2.8-4 offers ultra-wide zoom capability at very affordable prices. While superseded by newer Sigma Art and Contemporary designs, it provides useful wide-angle coverage for Nikon F mount photographers on a budget who need wider perspectives than standard kit zooms offer.