Sigma 20mm f/1.8 EX D DG Aspherical Autofocus Lens for Nikon Review

The Sigma 20mm f/1.8 EX DG is an older ultra-wide prime for Nikon F-mount DSLRs, offering a fast aperture and aspherical optics in a compact package. Designed for full-frame cameras, it delivers a wide field of view ideal for landscapes, architecture, and environmental portraiture. At its used price point around $162, it presents an affordable entry into fast wide-angle shooting for DX and FX Nikon bodies.

This lens predates Sigma's Art series and reflects the EX line's more modest build quality and optical performance. The f/1.8 maximum aperture provides shallow depth-of-field control and low-light capability rare in ultra-wides, though expect some vignetting and distortion at the edges, typical for fast wide primes of this generation. Autofocus is driven by a built-in motor, so compatibility and speed will vary by camera body. The 82mm filter thread is large for a 20mm lens, adding bulk and cost to filter systems.

For budget-conscious Nikon shooters seeking an ultra-wide with a fast aperture, the Sigma 20mm f/1.8 EX DG fills a niche, especially on the used market. It's best suited to careful shooters who can work around legacy optical quirks and don't need the sharpness or weather sealing of modern alternatives.