Sharpness

Sharpness at 19mm

For this test, the Sigma 19mm f/2.8 EX DN lens was attached to a Panasonic Lumix DMC-GF3 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 19mm

Centre sharpness remains high through from f4 to f/11, with f/16 and f/22 being adversely affected by diffraction. The edges aren't nearly as sharp as the centre, with f11 producing the sharpest results.

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