Sharpness at 28mm

The sharpness tests for this review were carried out using a real-world subject rather than a test chart. The Canon EF-S 17-55mm f/2.8 IS USM lens was attached to a Canon EOS 700D body, which in turn was mounted on a sturdy tripod. Self-timer mode was activated. Slight tonal changes are due to slight changes in natural light during the session.

The full frame at 28mm

Centre sharpness remains high through from f4 to f/11, with f/16 and f/22 being adversely affected by diffraction. The edges are almost as sharp as the centre, with f/4 to f/11 again producing the sharpest results.

Aperture	Centre Crop	Edge Crop
f/2.8
f/4
f/5.6
f/8
f/11
f/16
f/22