Canon EF 17-40mm F/4L USM vs Canon EF 24-70mm F/2.8L II USM — Which Is Better?

The Canon EF 17-40mm F/4L USM and the Canon EF 24-70mm F/2.8L II USM are both full-frame L-series zooms for the Canon EOS system, built for different jobs. The 17-40mm, released in 2003, starts at a true ultra-wide 17mm for landscapes, architecture and tight interiors. The 24-70mm II, released in 2012, spans standard to short-telephoto for portraits, events and general work.

The 17-40mm is the lighter carry at 1 lb 1.6 oz (500 g), against 1 lb 12.4 oz (805 g) for the 24-70mm II. It is also shorter, 3.82 in (97 mm) versus 4.45 in (113 mm), and slimmer at 84 mm versus 89 mm in diameter. That suits the 17-40mm to a compact kit built around wide scenes.

Filter threads differ: 77mm on the 17-40mm and 82mm on the 24-70mm II. Both accept front filters directly, so a shared filter collection fits only the matching thread size.

The f/2.8 aperture makes the 24-70mm II the stronger choice for dim reception halls and candlelit interiors, where the 17-40mm is limited to f/4 throughout its range. The wider aperture also allows shallower depth for separating a portrait subject from a busy background.

Each lens covers focal lengths the other cannot: the 17-40mm opens at an ultra-wide 17mm for sweeping views, while the 24-70mm II reaches 70mm for tighter framing of people. Close focusing favours the 17-40mm, which focuses as close as 0.9 ft (28 cm) against 1.2 ft (38 cm), and its maximum magnification is higher at 0.24x against 0.21x. Its internal zoom also keeps the barrel at a fixed length while zooming, where the 24-70mm II extends.

Both lenses are weather sealed, so dust and rain protection is not a deciding factor here. Neither offers image stabilization, and neither is teleconverter compatible.

The 24-70mm II adds a fluorine coating that helps dust and water slide off the front element for easier cleaning. It also has a zoom lock to stop the barrel creeping downward when carried. The 17-40mm has neither.

The 24-70mm II carries the more complex optical formula, with 18 elements in 13 groups against 12 elements in 9 groups for the 17-40mm. Their special-glass choices match: each lens uses one aspherical element plus low-dispersion glass that includes a super-low-dispersion element.