You asked
Is the sigma 35mm f 1 4 dg dn art sharp wide open?
I haven't got sharpness test results for this lens on the site, so I can't tell you how sharp it is at f/1.4. What the site does cover is the lens itself: a 35mm f/1.4 prime for full frame, with autofocus and no stabilisation. Its catalogue page lists a long run of full frame bodies from Sony, Leica and Panasonic.
Wide open, depth of field is very thin, so getting focus right on the eye matters more than small differences in sharpness. Portraits explains how that plays out at f/1.4 and when to stop down to f/2.8.
If you're looking at newer versions, the Sigma 35mm f/1.4 DG II Art is the 2026 redesign of this lens. For a refresher on what the f-number does, see the aperture section.
Written by Claude from this site's pages.