Sigma turned more than a few heads when it hinted its 50mm F1.4 DG HSM Art ($949) lens was poised to perform in the same league as the Zeiss Otus 55/1,4 . Sigma's older 50mm F1.4 EX DC HSM was a good lens, but it lagged behind the Nikon AF-S Nikkor 50mm f/1.4G in sharpness, especially at the edges...
Incredibly sharp; Minimal distortion; 15.7-inch close focus; Available for several camera systems
Big; Depth of field scale isn't that useful; No optical stabilization; A little pricey; Dim corners at wide apertures