Michael Topham puts Sigma’s latest wideangle zoom to the test and finds out if it lives up to the promise of producing zero distortion
Sigma 12-24mm f/4 DG HSM Art review – Features
Those familiar with the history of Sigma lenses will tell you that this isn’t the company’s first attempt at creating a 12-24mm ultra-wideangle zoom. It is in fact the third lens Sigma has produced covering this focal length, and it follows on from the Sigma 12-24mm f/4.5-5.6 EX DG that was announced in 2003, and the Sigma 12-24mm f/4.5-5.6 DG II HSM that was released eight years later. This third-generation lens has the promise of being Sigma’s best ultra-wideangle to date, with an entirely new optical design that incorporates 16 elements in 11 groups.
The lens leverages Sigma’s expertise in the processing and manufacture of aspherical lenses and incorporates three aspherical lenses produced with precision glass moulding. The most impressive aspherical element is found at the front, and with a diameter of 80mm, it’s the largest such element in this class of lens. It also features elements made from ‘F’ low-dispersion (FLD) glass, which, combined with the aspherical lenses, are designed to minimise distortion, chromatic aberration, coma and flare. To prevent flare and ghosting presenting problems when users shoot towards the light, Sigma has employed its Super Multi-Layer Coatings and has also equipped it with a permanent petal-shaped lens hood at the front.
The lens features a nine-blade rounded diaphragm to ensure it provides an attractive rendition to out-of-focus backgrounds with pleasing circular bokeh in the highlights. The lens’s maximum aperture (f/4) can be used right through the focal range and can be closed down to a minimum of f/22. As we’ve got used to seeing on most current Sigma lenses, it employs the manufacturer’s Hyper Sonic Motor (HSM). As well as driving the autofocus system smoothly and quietly, it presents full-time manual focusing; allowing users to adjust the focus manually at any time without the need to flick the AF/MF switch to manual first.
The minimum focusing distance of the lens is easy enough to remember – it allows you to focus within 24cm of a subject at the 24mm end of the zoom range. It has a maximum magnification ratio of 1:4.9 and is compatible with Sigma’s USB docking device that can be used to update firmware and refine the focus settings of the lens manually using the manufacturer’s Optimization Pro software.
The sheer mass of the lens implies it’s going to be best paired with full-frame DSLRs that feature the largest and most comfortable handgrips. However, there’s nothing to say it can’t be used with an APS-C DSLR, with which it’s also compatible. Attach it to an APS-C DSLR with a 1.5x crop factor and it’s equivalent to an 18-36mm lens, whereas on Canon APS-C DSLRs it has an equivalent focal length of 19-38mm. As with all lenses released by Sigma in recent times it’s available in three mounts and caters for Canon, Nikon and Sigma users.
As part of the boxed contents, there’s a rear cap and a sizeable front plastic cap that has a slim, felt-like lining on the inside. Unlike many other lens manufacturers, Sigma continues to supply its lenses with a padded case – something I’ve always found a rather nice touch and an extra precautionary measure that could prevent it getting knocked or damaged in transit.