Sharpness at 20mm

The sharpness tests for this review were carried out using a real-world subject rather than a test chart. The Tamron SP 15-30mm F/2.8 Di VC USD 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 20mm

Both center and edge sharpness are outstanding between f/4 and f/11, with f/2.8 just a little soft. At f/16 and f/22 sharpness is beginning to drop off a little due to diffraction.

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