Sigma 14-24mm f/2.8 DG HSM Art
Does Sigma’s latest zoom deliver on its promise of being the definitive wide-aperture, ultrawideangle zoom lens? Michael Topham finds out
michael Topham tests Sigma’s wide-aperture, ultra-wideangle zoom lens
The beginning of each year usually brings with it an influx of new cameras. Having tested most of these, we’re turning our attention to the interesting lenses that have entered the market. The Sigma 70mm f/2.8 DG MACRO | Art, the 105mm f/1.4 DG HSM | Art and the 14-24mm f/2.8 DG HSM | Art are all on their way, and it’s the widest of the three that has shown up first. It sits alongside Sigma’s 12-24mm f/4 DG HSM Art in the company’s line-up, and though not quite as wide, is a stop faster.
The optic has some excellent wideangle full-frame competitors. Nikon’s AF-S 14- 24mm f/2.8 G ED (£1,719) and Tamron’s 15-30mm f/2.8 SP Di VC USD (£929) are two rivals, with Canon’s closest offering being the EF 16-35mm f/2.8L III USM (£2,049).
At £1,399, this ultra-wideangle zoom is anything but cheap, and with its promise of delivering near-zero distortion and top-level image quality at every focal length, it sets our expectations extremely high. The lens we’re looking at is a bit of a brute, and Sigma hasn’t held back from making it as big and heavy as it needs to be to ensure the finest optical performance. The lens is optimised for a wide range of cameras, including those that have a 50-million-pixel resolution. Speaking to Sigma’s CEO, Mr Kazuto Yamaki, last year, I was told the company’s latest Art lenses are capable of being used with sensors higher than 50-million pixels. Although it hasn’t been confirmed, I’m led to believe the 14-24mm f/2.8 DG HSM Art is one such example.
In terms of optical construction, the lens is made up of 17 elements in 11 groups, with three ‘F’ low- dispersion (FLD) glass elements, three special low- dispersion (SLD) glass elements, and three aspherical lens elements, including one large- diameter aspherical element. The low- dispersion glass is used to curtail chromatic aberration, which is known for being problematic in large-aperture ultra-wideangle lenses. To prevent flare and ghosting when
shooting towards the light, Sigma has also employed its Super Multi- Layer Coatings. The nine-bladed aperture diaphragm can be set between a maximum aperture of f/2.8 and a minimum aperture of f/22. For smooth, quiet operation, the lens features Sigma’s Hyper Sonic Motor (HSM). In addition to driving the autofocus system, this offers 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.
At the 24mm end of the zoom range, the lens has a minimum-focus distance of 26cm. The diameter is 96.4mm at the widest point and with a length of 135.1mm, it’s stubbier than Tamron’s 15-30mm f/2.8 SP Di VC USD. The lens is also compatible with Sigma’s USB docking device, allowing users to update firmware and refine focus settings manually using the company’s Optimization Pro software.
At the time of writing, this lens is available in Canon, Nikon and Sigma mounts, but hopefully as the company introduces new E-mount Art lenses moving forwards, it’ll also recognise the demand for wideangles in E-mount and make this one available for Sony’s A7 series, too. Nothing is guaranteed, however. The lens is similar in design to Sigma’s 12-24mm f/4 DG HSM Art. Both weigh 1,150g and feature a bulbous front element that’s protected by a fixed lens hood. Such a large front element requires a push-fit lens cover and this has a felt lining to prevent it slipping off.
Assessing the build quality of the lens from the rear looking forwards, there’s a metal lens mount around which a rubber seal compresses against the camera mount to prevent moisture and dust creeping in. The barrel tapers out slightly to the zoom ring, which offers good grip and operates across its range in just under a quarter turn. The motion is consistently smooth through the zoom range, but as is to be expected of a lens that features large, heavy glass elements, it requires a little effort to shift the zoom from 14mm to 24mm and vice versa. Ahead of the zoom ring is a focus window, and offset from this is the only switch on the barrel. The AF/MF switch offers a satisfying click and a white background is shown behind the switch when it’s set to AF, which acts as a useful visual reference in low light. The diameter of the barrel widens beyond the focus distance window. Like the zoom ring, the manual-focus ring provides plenty of grip for those who might use it with gloves, and it operates fluidly across its focusing range of 0.26m to infinity.
To use the lens with filters you’ll need a specially designed ultra-wideangle system such as the Lee Filters SW150 Mark II. At present, a custom adapter hasn’t been made by Lee Filters for this lens, but we expect one in the near future. One of the first manufacturers to offer filter support for the lens is NiSi, who’ve recently released a new S5 filter kit (from £309), which can hold up to two 150mm filters, as well as an integrated circular polariser.
‘ The lens does an admirable job of keeping fringing under control’
pixel Canon EOS 5DS R. Shooting a variety of scenes, then analysing them closely alongside our laboratory tests, revealed that barrel distortion is present when the lens is used at the widest end of the zoom. That being said, this distortion isn’t as severe as one might expect for a lens so wide. Zoom in from 14mm and it soon disappears, and there’s virtually none between 18mm and 24mm. The lens is supported by an Adobe profile, so if you find yourself shooting at the wide end, correcting for distortion is a one- click fix: simply place a tick in the Enable Profile Corrections box in Lightroom CC or Adobe Camera Raw.
Our Image Engineering tests, which are carried out at each aperture setting at three focal lengths, reveal the lens to be at its sharpest in the centre at the wide end. Corner sharpness at 14mm peaks around f/8, where it’s similar to that in the centre. Zooming in to 18mm sees corner sharpness peak at around f/6.3 and the sharpness figure wide open at 18mm is slightly higher than that recorded at 14mm. Inspecting results at the long end of the zoom (24mm) tells us that centre and edge sharpness isn’t quite as good as it is at the wide end, but again, it improves by f/5.6 or f/8. The compromise of being able to shoot so wide at f/2.8 is the level of sharpness at the edge. The sweet spot of sharpness at any given focal length is between f/5.6 and f/8.
An inspection of images at 100% magnification revealed that the lens does an admirable job of keeping fringing under control. It was only in the brightest areas of a few test shots that I became aware of some green and purple fringes of colour, which were quickly dealt with by selecting the Remove Chromatic Aberration box from the Corrections tab in Lightroom CC. Vignetting does appear in images shot at f/2.8, but it gradually becomes less obvious as the aperture is closed down to f/5.6. Adobe’s Profile Corrections are very effective at alleviating vignetting from photographs taken at wide apertures.