Sigma’s range of Contemporary lenses are all about maintaining a balance between size, performance and price. They’re not smaller versions of the Art series lenses, which are meant to deliver the best possible image quality, regardless of size.
With a 55mm filter thread, and weighing 215g ( 7.58 oz) its diminutive size nicely complements the Sony a7/9 series and maybe also the larger Leica SL and Lumix S1 models [advertiser links], which it has also been designed for.
At around £549 / $549 [advertiser links], this all-metal lens is beautifully made. It even comes with a metal hood that’s oddly (and attractively) ridged on the outside but more importantly, nicely baffled on the inside to reduce flare and ghosting.
The lens itself has a ridged metal aperture collar with detents at third-stops, which feels silky-smooth and precise in operation. The manual focusing ring is also nicely machined and gives an assured grip. In use, the ring moves fluidly, though, as it’s a small lens, it is quite narrow and similar in width and feel to aperture ring. Not that you’re likely to use the focusing ring often, as Sigma has found room for a tiny AF stepper-motor, which on the Sony a7R III at least, is fast, smooth and practically silent.
Protection from the the odd knock and occasional spill is above average; focusing is internal and there’s no extending barrel. It’s not fully weather-sealed but there is a gasket around the bayonet mount.
Inside, it has eight elements arranged in seven groups and while it doesn’t have much in the way of esoteric glass like the Art series, it does have three aspherical elements. Sigma claims the optical design has been optimised to deliver smooth bokeh, with a ‘gradient to a soft blur’, something along the lines of the ‘feathered bokeh’ used in the design of the outstanding Olympus Pro F1.2 primes. It also has a usefully short minimum focus distance of just 24cm.
Image quality from the Sigma 45mm F2.8 DG DN | C is very good indeed. Sharpness is good wide open centrally leading to very good the frame across when stopped down.
Some slight spherical aberration is noticeable wide open but that has been left deliberately, much like the older, classic lens designs. Depending on your point of view, this either adds to or masks the quality of the bokeh but certainly lends to smooth transitions. After all, the double lined edges you sometimes see in the highlights are usually found in modern lens designs. There’s the slightest hint of that still though, with an additional but slight colour tint that’s sometimes referred to as ‘spherochromatism’ or ‘colour bokeh’.
There’s also some pincushion distortion which for a standard or ‘normal’ focal length like this is unusual but likely another of the compromises in the C series. Strangely, it’s not compensated for in the built-in profile that only applies lateral chromatic aberration correction and is mostly absent in images.
Some fringing (longitudinal) is apparent though if you zoom in (with purple rearward and cyan towards the front around high-contrast elements) but it’s minimal.
Ultra-fast lenses are all good and well but we need more, better quality primes with smaller apertures that are the same (or better) quality as the F1.4 models. This lens goes a long way towards that but, understandably, it’s still not quite at the level of excellence of the Art series. It’s not just the very good optical quality though that appeals, Sigma appears to understand that we photographers want smaller, lighter and better quality lenses. Even though there’s still some trade-off between price and performance at the initial aperture, perhaps it will be Sigma that takes the lead and offer comparable performance in a smaller form factor. If this lens is anything to go by, it certainly seems like they’re heading in the right direction.
Superb image quality
Thin MF ring
Sony E Pan/Leica L only