Sigma DG DN Contempory lenses are Sigma’s value line of lenses and might appeal to many shooters on a budget. All have pleasing bokeh and compact size and low weight. Available in Sony FE and L-Mount lens mounts, and so I wonder if the mount-specific lenses are tweaked for the differing sensor cover glass thickness.
Newly released are the Sigma 24mm f/2 DG DN Contemporary and Sigma 90mm f/2.8 DG DN Contemporary. Sigma has chosen to release 24mm lenses in both f/2 and and f/3.5 lens speeds—perhaps worth testing at some point; the f/3.5 ought to be ultra low distortion and very sharp by giving up 5/3 stop of lens speed, but perhaps not.
F/2 instead of f/1.4 is highly appealing in saving considerable weight and bulk since most of the time f/1.4 lens speed is only an awkward burden and hassle that also brings optical compromises (focus shift, field curvature, distortion all suck).
But Sigma’s f/2 “Contemporary” lineup is not aimed at best performance, but at economical pricing and pleasing image rendition.
With the exception of the world-class and extremely expensive Leica Summicron-SL ASPH designs, no manufacturer has yet targeted class-leading performance at modest lens speed.
What I’d rather see is f/2 and f/2.8 are additions to the Sigma DG DN Art lineup. Significantly better performance to the f/1.4 lineup should be readily achievable at the same price point, which for me would be far preferable to about-as-good performance for less money. I want to see as good or better sharpness, zero focus shift and very low distortion in an f/2 offering because those things have direct impacts on getting optimal results reliably.