Sigma 28-70mm F2.8 DG DN | Contemporary (L-Mount)

Reviewers found it sharp in the centre from f/2.8 across the range, with softness and vignetting confined to the extreme corners wide open; stopping down to f/5.6 or f/8 brings even results across the frame. One lab test found corners at 70mm fairly soft at large apertures. Focus breathing is almost absent, and autofocus is swift, quiet and accurate with eye tracking.

Bokeh is smooth in portraits but shows onion-ring texture in highlights, typical of zooms in this class. Ghosting and colour fringing are low, though the lens can produce flare against the sun. Distortion moves from barrel at 28mm to pincushion from 50mm. Testers rate it a strong lighter, cheaper alternative to 24-70mm f/2.8 zooms, with sealing only at the mount as the main caveat.