Sigma 85mm f/1.4 DG HSM Art review: Image quality
During our recent visit to the CP+ Camera and Photo Imaging Show we were told that this lens sets a new benchmark for optical quality in the Art series. With a statement like that we were expecting some remarkable results.
A few days after running it through a series of stringent lab tests mounted to an EOS 5D Mark III, I got the opportunity to pair it up with Canon’s 50MP EOS 5DS R. Inspecting my real-world images alongside our Applied Imaging chart indicates that it resolves outstanding sharpness in the centre when it’s used wide open (f/1.4) and things only get better when it’s closed down.
It transpires that it’s as sharp in the centre at f/1.4 as it is at f/11. Edge sharpness improves as the aperture is closed down and if you want to find the perfect sweet spot between centre and edge sharpness you’re best using it at f/5.6. Users can be confident of producing sharp results at f/8 and f/11, but the impact of diffraction does soften overall sharpness a little, particularly at f/16.
The aesthetic quality of the bokeh at f/1.4 is sublime. The dreamy blur can really accentuate subjects that you’d like to stand out from their surroundings and although vignetting is obvious at the lens’ maximum aperture, it’s not as severe as you might expect.
Edges appear approximately 1.3EV darker than the centre at f/1.4 and disperses completely by f/2.8. Optical performance isn’t compromised by distortion and it manages to control chromatic aberrations along high-contrast edges exceptionally well.
At the widest aperture there was just a hint of green fringing along a few edges of our test images, however this was a one-click fix using the Remove Chromatic Abberation tick box located beneath the lens corrections tab in Lightroom CC.