Sigma has quietly been strengthening its professional lens range with new models aimed at full-frame DSLRs. Not only has the company added a number of pro-worthy large-aperture primes but they’ve also taken the opportunity to revisit the constant-aperture zooms.

Arguably the single most important zoom in a pro-photographer’s armoury is the 24-70mm f2.8, and it’s a lens that must be bombproof – capable of landscapes, portraits and close-ups with equal aplomb. Sigma’s previous iteration was considered a solid performer but the new model has seen a complete overhaul and has been completely redesigned inside and out.

The new 24-70mm f2.8 IF EX DG HSM, to give it it’s full-name, hints at some of the new features, but it’s in the flesh that the lens impresses most. Unlike branded rivals the new Sigma is a short stubby affair, not quite 10cm long, with an enormous front element and 82mm filter ring. The wide body is purposefully designed to reduce corner shading on full-frame pro-cameras, but can be used without detriment on APS-C format DSLRs, becoming effectively a 35-105mm f2.8.

Thanks to a new inner-focus (IF) mechanism the overall length doesn’t change during auto-focusing improving balance and focus operation generally. The addition of a hyper-sonic motor (HSM) is one of the headline features, delivering not only a welcome speed bump but virtually noiseless focusing with real-time manual override, easily matching the Nikon and Canon rivals in performance – focusing speed especially. 

Build quality is equally impressive too, and several cuts above Sigma’s more consumer orientated model and feels both solid and durable but the lack of colour, save for some gold accents and lettering, a nod towards its optical quality, makes the outer quite sombre in appearance. Orange or yellow distance scales would know doubt help and be advantageous in low light, but it’s of no real significance overall.

Both focus and zoom rings are well damped with no looseness or sloppy action, of which rival brands aren’t always exempt. Indeed the zoom action is a little on the heavy side, but this preferable to it being too light from new, and will likely slacken off after time. However, unlike some of the very latest rivals, zooming increases the length, by about 20mm overall.

While the ergonomics are generally excellent, the bundled hood is tight fitting, necessitating some force both in fitting and then later with removal. All makers seem largely indifferent to hood design, with the big marques often being the worse offenders, and yet it plays a significant role in both handling and performance. The supplied petal shape hood isn’t particularly deep, but Sigma’s Super Multi-layer Coating technology is some of the best in the business and the 24-70mm seems essentially impervious to flare and ghosting.

In our real life shooting tests the Sigma performed very well throughout the zoom range. The resolution is excellent in the mid-range at 35mm from corner to corner, easily matching the highly regarded Canon EF 24-70mm f2.8 L through most of the aperture range – though it doesn’t quite have the same bite at maximum aperture.

It’s similar story at 70mm, it has superb contrast, excellent colour rendition and amazingly consistent resolution, but while it’s the equal at wider apertures it can’t quite achieve the equivalent results of the Canon when stopped down. If we have an anomaly it’s in the test results at 24mm. The Sigma has very good central sharpness, even wide open, but it’s let down by some softening at the edges and despite the use three aspheric lenses and the use of both Extraordinary-Low-and-Special-Low-Dispersion glass, there was higher than average chromatic aberration.

There were some other, albeit slight, weaknesses too. We expected some barrel distortion, but at 24mm, the Sigma has some waveform distortion that’s trickier to remove in post. It’s not impossible to correct though in Photoshop and it’s really only an issue with strong horizontal lines at the top and bottom edge of the frame. There was some vignetting wide-open too, noticeable just in the extreme corners, though that isn’t unusual at all and is easily removed from both JPEGs and Raw files with software. For all that, our real life shooting examples of landscapes, flowers and foliage at 24mm were utterly convincing, and at the longer focal lengths the Sigma really excelled.

At £920, the 24-70mm f2.8 IF EX DG HSM slots into their own range well, it’s much more costlier than the earlier model, which is being kept in range for now, but the optical improvements and fast, near silent focus operation is tempting, especially if this will be your main lens. It’s also true that the Sigma comes in comfortably lower in price than the camera marques – a pretty useful attribute in these times.  Nikon and Sony (Zeiss) have recently updated their models, but the Canon offering is several years old and may be modernized soon, possibly even with the addition of Image Stabilisation, if the rumours are to be believed. On the other hand the Sigma is here now and delivering results that would please the most hardened pro.

Final Verdict While there are both strengths and weaknesses, the Sigma 24-70mm f2.8 IF is without doubt a compelling alternative to rival marques OVERALL

Debbi’s passionate about all things photographic: from the latest digital kit to the greatest techniques to capture a scene. She’s been at the helm of the photography portfolio of magazines, websites and more for three years.