Sigma’s third f/1.4 prime lens for Sony E and Micro Four Thirds mounts has arrived. Michael Topham offers his verdict
Sigma 56mm f/1.4 DC DN Contemporary review: Image Quality
To get a good impression of how the lens performs on an APS-C mirrorless camera, it was predominantly used with Sony’s A6500 – a compact combination that was easy to slip into a jacket pocket and pull and out and use inconspicuously.
Shooting wide open at f/1.4 produces satisfying results, with sharply defined subjects standing out against smooth blurred backgrounds. The aesthetic of out-of-focus specular highlights at wide apertures is pleasing too, with nicely rendered circular highlights in the centre of the frame. Cats-eye bokeh was observed towards the edge at f/1.4, but this is less pronounced when you stop down. Centre sharpness is good at f/1.4, but stopping down and using it between f/2 and f/4 does yield sharper results. Corner sharpness also gradually improves as the aperture is closed to f/5.6.
With in-camera optical corrections switched off, vignetting is noticeable, with corners appearing approximately 1.2EV darker than the centre at f/1.4. I found the aesthetic of this corner shading to be complimentary to portraiture and centrally framed subjects. Vignetting becomes less obvious at f/2.8 and is barely noticeable at f/4.
For a fixed lens that’s equivalent to 84mm on an APS-C camera, I was surprised to find that it exhibits strong pincushion distortion when lens corrections are turned off. This wasn’t a major concern however as the built-in lens profile that was applied to a majority of my shots turned out to be highly effective at ensuring straight lines were kept straight.
Chromatic aberrations were also traced along high-contrast edges at f/1.4 when in-camera corrections were turned off. Some mild traces of purple and green fringes of colour were still obvious in shots where the built-in lens profile was applied, so you may find yourself applying some additional manual correction, just as I did.