Tamron 17-28mm F/2.8 Di III RXD

Reviewers found the centre sharp from f/2.8 at every focal length. The corners are weaker at 17mm wide open and good by f/5.6–f/8, and the 28mm end is the strongest overall. Chromatic aberration is low, but uncorrected vignetting and barrel distortion at 17mm are high, so it depends on lens profiles.

The RXD motor is quick and quiet for stills and video, though not as fast as Tamron's later VXD lenses on demanding tracking. Most testers saw it as a smart compromise: give up 1mm at the wide end, a few controls and some corner performance in exchange for a much smaller, cheaper lens.

Owners like how small the kit is with the 28-75 and 70-180 sharing 67mm filters, and many call it the ultra-wide they actually carry. Real-estate, travel and vlog shooters report reliable AF and good colour.

Common complaints are the 17mm start rather than 16mm, soft extreme corners for astro wide open, and the lack of an AF/MF switch or custom button. Some note dust ingress over time and visible distortion if profiles are disabled.