As with other Art lenses, the dust- and splashproof 135mm feels robust and has a classy all-black finish. A very wide manual focus ring dominates the front half of the barrel, with a grooved rubberised finish that makes it very easy to use. Behind it is a small focusing distance window and to its left are two focus switches. The top switch selects AF or manual focus, while below it is a focus limiter with three settings: Full, 1.5m to infinity and 0.875m-1.5m.
The lens is designed for use with the latest high-resolution cameras and boasts two SLD (Super Low Dispersion) glass elements and two FLD ('F' Low Dispersion) glass elements, as well as Sigma's Super Multi-Layer Coating, to maximise sharpness and minimise aberrations, flare and ghosting. Sigma's tried-and-tested Hypersonic motor (HSM) technology handles autofocus.
Our lens was used on a Canon EOS 6D and EOS 5D Mk II and it handled beautifully. The focus is extremely fast and quiet and works very well in low light/low-contrast situations. Image quality is superb, with excellent sharpness throughout the aperture range, including when the lens is used wide open. This, married with the extremely shallow depth-of-field and stunning bokeh effect, means you'll want to shoot at f/1.8-2 most of the time. Take care though as focus must be exact. Distortion and light fall-off are well handled and contrast is excellent, with the deep hood providing sufficient shade when used on sunny days.
One factor to be aware of though is that image blur, due to your movement, can be a problem due to the weight of the lens and its focal length. Rather than aiming for 1/150sec as your minimum shutter speed, I'd suggest 1/250-1/350sec as a safer option.
There aren't many competitors to the Sigma – the (£959) Canon and (£1,040) Nikon are brilliant but older f/2 lenses, but the Sigma is worth the extra cost. Samyang's (£449) 135mm f/2 is also excellent but manual focus, as is the (£1,700) Zeiss Milvus. If you want the ultimate fast autofocus 135mm portrait lens, this Sigma is it.
Spending over a grand on a lens is rarely an easy decision to make, but the qualities of this Sigma Art lens are such that if you're a dedicated portrait photographer, you'll want to start saving for one. An absolutely stunning piece of glass.
Guide Price: £1,149
Lens construction: 13 elements in ten groups
Number of diaphragm blades: Nine (rounded)
Angle of view: 18.2°
Minimum aperture: f/16
Minimum focusing distance: 87.5cm
Maximum magnification: 0.2x
Filter Size: 82mm
AF Fittings: Canon, Nikon, Sigma, Sony E, L-mount
Supplied accessories: Case, hood, front & rear lens caps