Sharpness at 18mm

The sharpness tests for this review were carried out using a real-world subject rather than a test chart. The Canon EF-S 10-18mm f/4.5-5.6 IS STM lens was attached to a Canon EOS 1200D 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 18mm

Centre sharpness remains high through from f/5.6 to f/11, with f/16 and f/22 being adversely affected by diffraction. The edges aren't nearly as sharp as the centre, with f/8 to f/11 producing the sharpest results.

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