Super-wide-angle zooms are difficult to design and for this reason tend to be pretty expensive to buy. And while you can usually expect a price gap between independent lenses and those from the camera maker, here it seems even wider than ever.

Let’s say you have a Canon body. This lens will cost you around £400 at current street prices, but Canon’s own EF-S 10-22mm is nearer £650. Or, if you’ve got a Nikon, the nearest equivalent is the new Nikon 10-24mm, which weighs in at an eye-watering £800. So there are huge cost savings to be made by choosing an independent super-wide-angle lens over the maker’s own, then, but is this reflected in the build quality and the optical performance?

Right from the start of this lens’s inspection, it’s obvious there’s nothing wrong with the Sigma’s build quality. It has Sigma’s trademark matt black finish, which looks good and feels tough. The zoom ring is clearly marked and has an extremely smooth and well-weighted feel. The front section extends slightly as you zoom, but there’s absolutely no play in the mechanism, which feels rock solid. On the side of the lens is a firm and positive AF/MF switch, but this lens also features full-time manual override, so if you don’t like the camera’s focus point you can give the focus a final tweak before you press the Shutter button the rest of the way. Like this zoom ring, this focus ring has a smooth, top-quality feel. There’s a focus distance scale under a window on the top of the lens barrel too, and the only other thing you could possibly ask for would be depth-of-field markers to help exploit the massive depth of field at these focal lengths. Sadly, though, this just isn’t possible on a zoom lens. Overall, this feels like a weighty, classy piece of kit. It might slightly overpower smaller bodies, but it’s a perfect match for a mid-range/semipro SLR.

So what about its optical performance? It’s good news here too. On our EOS 400D, it didn’t quite deliver the peak resolution figures we’ve seen with some lenses, but it was consistently up at around the 1600 line widths/picture height mark, which is a good standard for a DSLR. Once you get to this level, your picture-taking technique, the RAW converter you use and any sharpening settings you apply will easily mask small differences in definition between lenses.

The Sigma’s one weak spot was at full aperture at 10mm, where the centre of the image proved none too sharp and the edges were softer still. Going down one stop to f5.6, though, made a big difference. This is a lens you can use at any aperture (except f4!) and at any focal length without worrying whether you’re working in its ‘sweet spot’.

However, definition isn’t the only quality to look for in a super-wide-angle zoom – distortion and chromatic aberration are just as annoying, and not always easy to put right in software.

The Sigma, though, shows unusually low levels of both. There is some chromatic aberration at 10mm, though not a lot by super-wide-angle standards, while at longer focal lengths it’s all

but absent.

It’s at the 10mm end that the distortion is most noticeable, and what could prove tricky for those who like to correct distortion on the computer is that it doesn’t have a simple shape. Straight lines stay remarkably straight until they get to within 25 per cent or so of the frame edge, and then they start to bend. It makes most pictures look better, but it also makes the others hard to fix.

As usual with zooms, the barrel distortion turns to pincushion distortion at longer focal lengths. It’s noticeable when you’re shooting test targets, but may not be so apparent in real-life photography. Overall, the Sigma’s distortion control is pretty good, especially at the wide-angle end where the designers have confined the worst of it to the edges of the frame, where it’s less likely to be noticed.

The thing that was striking about the Sigma was how pleasant it was to use, and this is the sort of thing that doesn’t show up in test charts. The build quality and controls do make a difference, and if you actually like using a piece of kit you’re going to get a lot more out of it. And a lens like this one really does open up whole new perspectives in every sense.

The most obvious benefit is the ability to squeeze more into the frame – handy for cramped interiors or big, sweeping landscapes. But super-wide-angle lenses also dramatically change the size relationships between nearby and distant objects. Telephoto lenses are known for ‘flattening’ perspectives, but lenses like this one really exaggerate it. By the time you’ve got close enough to an object to fill the frame, it appears dramatically larger than whatever is in the background.

The effects are creative as well as practical, then, so it’s well worth investing in a lens like this to see just how it affects the mood and appearance of your pictures. And given the fact that the Sigma is both good and relatively affordable, why put it off any longer?

Final Verdict Optically this lens is very good, but what really stands out is its build quality, smooth controls and general handling OVERALL

Our lens reviewer, and technical expert, Rod is a veritable photographic encyclopaedia. His illustrious CV has seen him write for many mags, websites and journals.