Sharpness at 500mm

For this test, the Sigma 500mm f/4 DG OS HSM Sports lens was attached to a Canon EOS 5D Mark III body, which in turn was mounted on a sturdy tripod. Exposure delay mode were and mirror lockup were activated. Tonal and colour variances across the crops are due to changes in natural light during the session.

The full frame at 500mm

Both the centre and edge sharpness are excellent wide-open at f/4, and outstanding from f/5.6 through to f/16, with f/22 and f/32 being adversely affected by diffraction.

Aperture	Centre Crop	Edge Crop
f/4
f/5.6
f/8
f/11
f/16
f/22
f/32