Leica Super-Vario-Elmar-SL 16-35 f/3.5-4.5 ASPH.

Testers found it sharp, with good detail across the frame, but measured results were good rather than outstanding: edges soften at wider apertures across the zoom range, while the centre holds up well. Distortion is low for an ultra-wide zoom, and colour fringing is hard to find in corrected files, though uncorrected raw files show more lateral chromatic aberration than usual. Vignetting is visible at maximum aperture and mostly gone by f/5.6. Bokeh is smoother than expected for a wide lens.

Autofocus is quick, near silent and fine for video and tracking, if not the snappiest. Build quality is top class, with an all-metal sealed barrel, internal zoom and a non-rotating front. The criticisms are size and weight for an f/3.5-4.5 lens, a wide rectangular hood, flare artefacts when pointing at bright lights, and a very high price, which makes it a niche lens even if its range is useful every day.