Sharpness at 105mm

The sharpness tests for this review were carried out using a real-world subject rather than a test chart. The Canon EF 24-105mm f/3.5-5.6 IS STM lens was attached to a Canon 5D Mark III 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 105mm

Center and edge sharpness are soft wide open at f/5.6, but are excellent between f/8 and f/11. At f/16 sharpness across the frame is beginning to drop-off a little due to diffraction, but is still commendably high. F/22 and f/32 are best avoided.

Aperture	Centre Crop	Edge Crop
f/5.6
f/8
f/11
f/16
f/22
f/32