Canon EF 16-35mm F/4L IS USM vs Canon EF 17-40mm F/4L USM — Which Is Better?

The Canon EF 16-35mm F/4L IS USM and Canon EF 17-40mm F/4L USM are both L-series full-frame zooms for the Canon EOS system, so either mounts directly on any Canon EF camera. The 16-35mm arrived in 2014, eleven years after the 17-40mm.

Both are constant F/4 wide-angle zooms for landscape, architecture and reportage work. The choice comes down to focal range, stabilisation and optical construction.

The 17-40mm is the lighter, shorter carry: it weighs 500 g against 615 g and measures 97 mm long versus 112.8 mm. Diameters are nearly identical at 84 mm and 82.6 mm.

Filters are a similarity rather than a difference: both share a 77mm front filter thread, so one set of polarisers and ND filters serves both lenses.

The 16-35mm gives you a wider view for tight interiors and sweeping landscapes, starting at 16mm instead of 17mm. The 17-40mm answers with 5mm more reach at the long end, reaching 40mm for slightly tighter framing without changing lenses.

Their maximum apertures are a similarity: both hold F/4 across the zoom range, so neither offers a light-gathering advantage. Both also focus to 28cm for close foreground detail, with maximum magnifications of 0.23x and 0.24x.

The 16-35mm is the only one of the pair with built-in image stabilisation, rated at 4 stops, for handheld interiors, dusk cityscapes and static scenes at slower shutter speeds. The 17-40mm leaves those situations to a tripod or other support.

It also has a fluorine coating on the front element, so dust and fingerprints wipe off the exposed glass more easily in dirty or wet conditions. Weather sealing is a shared strength, guarding both lenses against moisture and dust.

The 16-35mm uses internal focusing, so the barrel does not extend while you focus, whereas the 17-40mm's front section moves during focusing. A fixed length helps when shooting close to glass, walls or flower beds.

Its optical design is also the more elaborate of the two, with 16 elements in 12 groups including three aspherical elements and two low-dispersion elements. The 17-40mm uses 12 elements in 9 groups with one aspherical, one low-dispersion and one super-low-dispersion element.