Sharpness at 45mm

For this test, the Sigma 45mm F2.8 DG DN lens was attached to a Sony A7R III body, which in turn was mounted on a sturdy tripod. Exposure delay mode was activated. Tonal and colour variances across the crops are due to changes in natural light during the session.

The full frame at 45mm

Centre sharpness is good wide open at f/2.8, and outstanding through from f/4 to f/16, with f/22 being adversely affected by diffraction. Edge sharpness isn't quite as good, with the best results achieved between f/5.6 to f/16.

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