Canon EF 16-35mm F2.8L III USM

The Canon EF 16-35mm f/2.8L III USM is the third generation of Canon's f/2.8 ultra-wide zoom for EF-mount SLR cameras. Canon announced it on 25 August 2016 together with the EOS 5D Mark IV and the EF 24-105mm f/4L IS II USM. It targets landscape, architecture, astro and interior work on full-frame and APS-C EF bodies.

Optical design

The lens has 16 elements in 11 groups. Canon's Camera Museum lists three aspherical lenses, two large-diameter glass-molded aspherical lenses and one ground aspherical lens, plus two UD lenses. The aperture is a constant f/2.8, with a smallest aperture of f/22 and a 9-blade circular diaphragm. Canon says that the Subwavelength Structure Coating (SWC) and Air Sphere Coating (ASC) significantly reduce flare and ghosting. Canon calls the design all-new, with major gains in outer and corner sharpness over the previous version. The maximum magnification is 0.25x at 35 mm.

Autofocus and handling

Autofocus uses inner focusing with a Ring USM. The minimum focus distance is 0.28 m. The lens has no optical stabilizer. Canon describes the construction as highly resistant to dust and water intrusion. As an EF lens, it needs the EF-EOS R adapter on RF mirrorless bodies.

Build and size

The lens weighs 790 g and measures 88.5 mm in diameter and 127.5 mm in length. The filter thread is 82 mm.

Where it fits

The predecessor, the Canon EF 16-35mm F2.8L II USM, weighs 635 g in our database and is shorter at 112 mm with 16 elements in 12 groups. The newer version is heavier and longer but has the redesigned optics. The EF 16-35mm F4L IS USM (615 g, with stabilizer) and the EF 17-40mm f/4L USM (500 g) are lighter and slower alternatives. The EF 11-24mm F4L USM goes wider but is much larger.

Pros and cons

Pros

• Constant f/2.8 at 16-35 mm
• All-new optical design with improved edge and corner sharpness according to Canon
• SWC and ASC coatings against flare and ghosting
• Dust and water resistant construction
• 0.28 m minimum focus distance

Cons

• 790 g is heavier than the EF 16-35mm F2.8L II (635 g)
• 82 mm filter thread, larger than on the f/4 alternatives (77 mm)
• No image stabilizer
• EF mount needs an adapter on mirrorless bodies

Verdict

The EF 16-35mm f/2.8L III USM is the high-end choice for EF shooters who want a fast ultra-wide zoom. It is bigger than the earlier version and the f/4 alternatives, and its main selling point is the redesigned optics and coatings.