Sigma 17-70mm f/2.8-4 DC Macro OS HSM test

The majority of digital SLRs sold in the UK are supplied in kit form with an 18-55mm zoom, which while representing a good starter lens, isn’t the sharpest of optics. For most amateur photographers, this zoom will be the main optic of choice until they gain experience and are ready to expand their outfit. Any additional lens will usually cover different focal lengths, such as a telezoom or ultra wide-angle, which means that most will rarely, if ever, give serious considerations to upgrading their original standard zoom.

However, take a look at the lens ranges of the DSLR manufacturers and brands like Sigma and Tamron and you’ll see that all have alternatives on offer. The reason for this is simple. The standard zoom is a very versatile lens, covering focal lengths that make it ideal for subjects ranging from landscapes at its wide end through to portraits at its tele end, with the focal lengths between being suitable for all types of general photography. It’s no surprise then that it remains a fixture on most DSLRs, which is why upgrading it makes such good sense – if you’re taking so many pictures with a standard zoom, why not buy one that offers a superior optical performance?

The Sigma 17-70mm f/2.8-4 DC Macro OS HSM was released earlier this year. It’s nicely designed, compact and has a solid, well-made feel. Despite the fact it boasts a fast f/2.8-4 maximum aperture, its front optic isn’t that wide. The filter thread of 72mm is the same as many telezooms, which may save screw-in filter users money on duplicate filters. Another bonus is that the front element doesn’t rotate during AF, so if you’re using a slot-in grad filter, for example, you won’t have to adjust its position after focusing. Optically, the Sigma boasts three aspherical elements and an ELD (Extraordinary Low Dispersion) glass element to help minimise aberrations.

It’s designed for use with APS-C sensors, giving an effective focal length of 25.5-105mm (Canon: 27.2-112mm). Used on DSLRs with a larger sensor results in vignetting and isn’t recommended.
It’s a very easy and practical lens to use. The zoom and manual focus rings are wide and have an easy to grip grooved finish. Both have a smooth weight to their action, and while the manual focus ring is lighter and easier to move, it’s not so loose that it's easy to accidentally knock out of position. The main controls are on the left side of the barrel. These are the AF/M focus switch, a zoom lock to prevent the barrel accidentally extending, and the on/off switch for the Optical Stabiliser (OS). This latter feature, which Sigma claims has a four-stop benefit, will prove more useful for Canon and Nikon owners, as most Pentax and Sony DSLRs have body-integral stabilisation, although Sigma states its OS can benefit these users too.
The Sigma proves to be a very practical and enjoyable lens to use. The faster aperture gives a brighter viewfinder image and the OS does make a difference when shooting in low light without the aid of a tripod. The Hyper Sonic Motor (HSM) ensures that autofocus is fast, responsive and very quiet. It’s worth noting its close-focusing capabilities too: while it’s no rival to a dedicated macro lens, its minimum focus of 22cm and 1:2.7 reproduction ratio (around 1/5th life-size) is very useful when you want to focus on smaller details.

Optical quality is a strong factor in this zoom’s appeal, with sharpness, distortion and contrast proving far better than you could hope for from your kit zoom. Image sharpness is very good throughout the range of focal lengths, even at maximum aperture, although closing the aperture by one stop does lead to slightly better results. Its best performance at all focal lengths is between f/4-11, with excellent sharpness at 17mm. While sharpness tails off at a slow rate as you zoom through the range, it is still very good at 70mm, but we suggest you avoid using the minimum aperture whenever possible. It’s worth noting that edge sharpness in general is very good, distortion is only slightly evident at 17mm and chromatic aberrations are very well controlled.

 Guide Price: £409 / Street Price: £330
Lens Construction: 17 elements in 13 groups
Maximum aperture: f/2.8-4
Minimum aperture: f/22-32
Angle of View: 72.4º - 20.2º
No. of diaphragm blades: Seven
Minimum focus: 22cm
Maximum magnification: 1:2.7
Dimensions / Weight: 79x88.9mm / 520g
Supplied Accessory: Petal-shaped hood and caps
AF fittings: Canon, Nikon, Pentax, Sigma & Sony
PHONE: 01707 329999
WEBSITE: www.sigma-imaging-uk.com


Verdict:
This is a standard zoom that won’t disappoint. It offers a very good range of features, including a fast maximum aperture and OS. However, it’s the optical quality that impresses most. A deserved Best Buy.

Like: Optical quality; internal focusing; fast aperture; optical stabiliser
Dislike: Nothing major to complain about
Handling: 4/5
Features 4/5
Performance 4.5/5
Value: 4.5/5
Overall: 4.5/5