Sharpness at 16mm

For this test, the Sigma 16mm F1.4 DC DN C lens was attached to a Panasonic G9 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 16mm

Centre sharpness remains high through from f/2 to f/11, with f/16 being adversely affected by diffraction. The edges aren't quite as sharp as the centre, with f/2.8 to f/11 producing the sharpest results.

Aperture	Centre Crop	Edge Crop
f/1.4
f/1.8
f/2
f/2.8
f/4
f/5.6
f/8
f/11
f/16