Sharpness at 500mm

Our sharpness tests are carried out by photographing a real-world subject rather than a test chart. The Tamron 150-500mm F5-6.7 Di III VC VXD was attached to a Sony Alpha A7 III camera, which in turn was mounted on a sturdy tripod. Self-timer mode was activated to steady the camera completely. Any slight tonal changes you may see across the crops are a result of slight changes in natural light during the shooting session.

The full frame at 500mm

At both the the centre and the edges of the image, sharpness is a little soft at the maximum aperture, sharpening up at f/8.

It maintains that level of sharpness until f/22, where it remains excellent but is ever-so-slightly softer due to diffraction.

Aperture	Centre Crop	Edge Crop
f/6.3
f/8
f/11
f/16
f/22
f/29