Sharpness at 100mm

The sharpness tests for this review were carried out using a real-world subject rather than a test chart. The Tamron 100-400mm F/4.5-6.3 Di VC USD lens was attached to a Canon 5DS R 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 100mm

Both center and edge sharpness are wide-open at f/4.5 and excellent from f/5.6 through to f/16. At f/22 sharpness is beginning to drop off due to diffraction.

Aperture	Centre Crop	Edge Crop
f/4.5
f/5.6
f/8
f/11
f/16
f/22
f/32