Sigma's latest offering in the Art Lens portfolio is an ultra-wide 20mm full frame lens, for Nikon, Canon and Sigma fit. Not only that, but an extra-bright f/1.4 aperture makes this a desirable optic from the start. All looking good in theory, now let's see how it handled and performed in practice.

Superb optical quality; Well made; High control of CA; Excellent handling; Excellent AF performance

Price penalty for f/1.4 aperture; Heavy and bulky; Not weather resistant

During the last decade the ultra-wide segment has been dominated by zoom lenses but it seems as if prime lenses are about to enter a renaissance. Lately Nikon released a 20mm f/1.8 and we've seen a bunch of updates from Zeiss and some promising announcements from a new player (irixlens.com).

The Sigma 20mm F1.4 DG HSM is a very fast, tack-sharp prime lens in Sigma's excellent Art series, and also a unique lens to boot, as it's the only 20mm lens in the World to offer an f/1.4 aperture.

In my opinion, one of the best developments to happen in photography recently is the stepped-up offerings of third party...

I have only had this lens for about a month, but I will share my limited experience of using it. The first thing that hits you is the physical size - its a large, heavy lens (950G) and I really had to tighten the tripod up like never before when using it.

For the past couple of months, I've been incredibly busy testing gear from many different manufacturers. But as many of you know who have been readers of this blog for a while, I switched all my DSLR lenses over to Sigma a couple of years back. Why

Wow. Right, that's why they call it "glass." Beyond a bit of plastic and electronic wizardry that's all this thing is: GLASS. Absolutely incredible imagery. Beautiful wide angles with no discernible distortion. Insane, insane, insane depth of field and bokeh.

During the last decade the ultra-wide segment has been dominated by zoom lenses but it seems as if prime lenses are about to enter a renaissance. Lately Nikon released a 20mm f/1.8 and we've seen a bunch of updates from Zeiss and some promising announcements from a new player (irixlens.com).