If you’ve read any of our recent reviews on the rather lovely Sigma range of Art lenses, you’ll know that the company has been producing some great optics for the money. The problem is not everybody wants to step up to that price band and may want a lighter weight solution or some added extras like image stabilization. In this regard, standard zooms like the Sigma 17-50mm f/2.8 EX DC OS HSM can fit the bill.
The lens has a good wallop of overall features and covers most of the bases you would want from a wide-angle zoom. But, does this mean the lens is a good alternative to the rest of the pack and can it deliver in the real world? Let’s dig in and see what this lens is all about.
The basic features on the Sigma 17-50mm f/2.8 EX DC OS HSM are as you would expect from a medium-priced zoom lens. Designed specifically for a crop sensor camera body, the lens can work on a full-frame offering with the equivalent focal range of 24-82mm.
It has a constant aperture of f/2.8 going to f/22, a step up from a kit lens which usually starts at f/3.5 and is variable. Optical stabilization is thrown in for good measure to round off the overall features.
The lens barrel itself is constructed from tough, composite plastics. It has a solid feel, ideal for general use, but not as hardy as an all-metal construction. It’s also not weather-proofed, but you could argue the majority of the Art series are in the same camp, which means this shouldn’t be a dealbreaker.
The layout on the lens barrel is simple and straightforward. A substantial zoom ring with a smaller manual focus ring, both with reasonably smooth operation. The lens barrel features a zoom lock switch, a manual and autofocus switch and also a switch for turning on and off the stabilization system.
Inside the lens are seven elements arranged in 13 groups, with two ‘F’ Low Dispersion (FLD) elements to reduce anomalies such as chromatic aberration and to cut down on lens flare. There are also seven rounded diaphragm blades within, leading up to a 77mm filter thread, which is nonrotating, so you can fit your favorite filters.
The Optical Stabilizer (OS) is also rated at providing four stops handheld, which should do a good job of dropping shutter speeds. Also included is the more efficient Hyper Sonic Motor for quicker autofocusing which should be quieter than cheaper units. Everything here weighs in at a reasonable 565g.
The Sigma 17-50mm f/2.8 EX DC OS HSM in Use
When the Sigma was attached to our test camera, a Nikon D7000, it balanced extremely well and felt lightweight enough to be carried around all day long. The lens extends forward when zooming, with just the right amount of feedback and resistance throughout the focal range.
The autofocus system does a very good job of snapping into place, especially when presented with a good degree of light. This was also the case with moderate indoor light, but when light levels really drop, the lens can hunt for focus. Not too dissimilar from many f/2.8 zooms in this price range, which means it’s an overall good performer, unless in the darkest of conditions.
The overall sharpness of the Sigma 17-50mm f/2.8 EX DC OS HSM has its optimal zone between f/5.6 and f/8. It’s also the sharpest in the middle of the focal length, around 27mm. With the aperture fully wide open at 17mm, the lens has noticeable edge softness, with reasonable center sharpness.
Stopping down to f/4 starts to bring the whole frame into sharper focus, while at f/11 sharpness starts to tail off a little. At 50mm, resolution starts to decrease as at its widest. Basically, this is a lens that works at it’s best in the middle zone of focal length and aperture.
This is also true with lens anomalies such as barrel distortion. This is most evident at 17mm, with the cleanest setting being 34mm. At 50mm the effect is less pronounced, but still suffers from some pin cushioning. The same goes for chromatic aberration, which was lower than expected, but can show up at both ends of the focal range on high contrast areas. As usual, editing software can reduce this effect.
When it comes to manual focusing, there’s not much leeway between the minimum focus distance and infinity. The manual focus ring only needs turning ever so slightly to dramatically change sharp focus, so this is best done in live view when mounted on a tripod. In fairness, this type of lens is designed to be mostly used in autofocus mode, but a wider-ranging focus ring would have expanded the lens’ features.
Although the Sigma 17-50mm f/2.8 EX DC OS HSM isn’t specifically a macro unit, it can focus as close as 28cm, with a ratio of 1:5. At the more telephoto end of the focal range, the lens can create detailed images when close-up and can produce interesting large depth of field images when at the wide focal length.
As for overall image quality, the Sigma 17-50mm f/2.8 EX DC OS HSM produces pleasing images with a good degree of contrast. In the middle of the focal and aperture range, the lens gives the best detail, but that’s not to say the extremes can’t produce good results. Just a touch behind the medium settings.
The optical stabilization system works very well, providing up to four stops, which works great for low light conditions. At this price point and coupled with an aperture of f/2.8, it means the functionality of the lens is extended over what you could find from a regular kit lens.
How Does It Compare?
When it comes to comparing the Sigma to the rest of the competition, the choices will depend largely on your camera body and price point. The Sigma can fit Canon, Nikon, and Sony mounts, which means the Sigma goes up against a wide range of lens possibilities.
As we used the Nikon D7000 on this test, the Nikon AF-S DX NIKKOR 17-55mm f/2.8G IF-ED could be a possible solution, but it’s considerably more expensive. The same goes for the Canon EF-S 17-55mm f/2.8 IS USM, which is a great wide-angle zoom that has image stabilization, but you’re also paying more than double for its lovely features.
The Tamron SP 17-50mm f/2.8 XR Di II VC, although slightly more expensive than the Sigma, offers comparable quality, with a constant f/2.8 aperture. This means that the Sigma sits in a happy medium place, at least price point-wise, with good quality optics and feature set for the money.
|Sigma 17-50mm f/2.8 EX DC OS HSM||Tamron SP 17-50mm f/2.8 XR Di II VC|
|Elements||17 elements/ 13 groups||19 elements/ 14 groups|
|Blades||7 rounded||7 rounded|
The Sigma 17-50mm f/2.8 EX DC OS HSM sits in an ideal place. It’s a fair step up from the standard zoom kit lens and is excellent for those who want good optical quality but don’t want to spend top-end prices. The Sigma is capable of producing some very good images, most notably in the medium focal length and aperture range, but the extremes are still acceptable in the right circumstances.
The optical stabilization and f/2.8 aperture are going to be useful in low light conditions, with the lens being very efficient to snap into focus in everything but the lowest of light.
There are obviously caveats, such as a non-metal construction, sensitive manual focus ring, and soft edges when wide open, but as a complete package, the Sigma 17-50mm f/2.8 EX DC OS HSM has a lot to offer for the money. The Sigma may not be the only consideration as a wide-angle zoom on the market, but it does tick a lot of boxes as a solid, all-rounder.