Sigma 28-70mm F2.8 DG DN | Contemporary

Reviewers found it sharp in the centre from f/2.8 across the range, with corners that lag a little at 28mm wide open and improve by f/4 to f/5.6. Its optical quality sits close to the 24-70 Art and the Tamron 28-75mm G2, at a noticeably lower weight than either.

The stepping-motor AF is quick and quiet for stills and video, though not quite as fast as Sony's linear-motor zooms when tracking. Testers point out that it depends on in-camera correction for distortion and vignetting, and that the lack of a 24mm wide end and the minimal sealing are the price of its small size.

Owners like it as a travel and walkaround f/2.8 zoom that does not make an A7-series body feel front-heavy, and many bought it to replace a heavier 24-70. The close-focus ability and the 67mm filter size shared with other Sigma DG DN lenses are frequent positives.

The common complaints are missing 24mm on the wide end, a zoom ring that some find stiff when new, and the absence of switches beyond AF/MF. A few users note that the barrel extends when zooming and that the plastic-feeling TSC barrel feels less premium than Sigma's Art lenses.