Leica Vario-Elmarit-SL 24-70 f/2.8 ASPH.

Reviewers find it sharp in the centre across the whole zoom range, with only the extreme edges softening slightly at f/2.8 and the best edge results from about f/4 to f/11. Flare into the sun is well controlled, bokeh is pleasing, and the build is excellent: all-metal, sealed and with a metal hood. Distortion (barrel at 24mm, mild pincushion at 70mm) and wide-open vignetting are noticeable but correct easily.

The recurring reservation is value. Testers note that it shares its optical design with Sigma's 24-70mm f/2.8 DG DN Art and could not find an image quality difference, so the premium buys the Leica build and name. They also miss the Sigma's AF/MF switch, zoom lock and AFL button. Next to the 24-90 it is clearly smaller and about 300g lighter, slightly sharper at the corners at 24mm and slightly behind at longer focal lengths.