Sharpness at 70mm

For these sharpness tests the Sigma 70mm f/2.8 DG Macro Art lens was attached to a Canon EOS 5DS R body, which in turn was mounted on a sturdy tripod. Slight tonal changes are due to slight changes in natural light during the session.

The full frame at 70mm

The centre is very sharp, even wide-open at f/2.8, with peak performance achieved in the f/4-f/11 range. Diffraction is only really noticeable at f/22.

The edges are slightly soft at f/2.8, sharpening up sufficiently at f/4, with f/5.6-f/11 the optimum aperture range.

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