To examine the relative sharpness and contrast of these two optics, we photographed an industry standard resolution chart with both Ultra Wide Zoom EF lenses using a single Canon EOS 5D Mark II DSLR. We tested both lenses at a range of apertures and focal lengths. The results, once again, show impressive output from the slower (and much less costly) 17-40mm Canon lens.

Measured in Line Widths per Picture Height (LW/PH), we’re seeing better raw resolution numbers from the 17-40mm USM lens at its widest aperture (f/4 on the Canon 17-40, f/2.8 on the Canon 16-35 II). At maximum aperture, the 17-40mm at f/4 yields slightly more edge definition and better contrast than the 16-35 at f/2.8.

Canon EF 16-35mm II @ f/2.8

Canon EF 17-40mm @ f/4.0

At two stops down - near optimal aperture - the lenses look almost identical, though the edge in sharpness shifts to the 16-35mm lens.

Canon EF 16-35mm II @ f/4.5

Canon EF 17-40mm @ f/6.3