Sharpness at 50mm

For this test, the Samyang AF 50mm f/1.4 FE lens was attached to a Sony A7R II 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 50mm

Centre sharpness is disappointing when shooting wide-open at f/1.4, acceptable at f/2, and very good from f/2.8 onwards, with f/16 being adversely affected by diffraction. The edges aren't quite as sharp as the centre, with f/5.6-f/11 producing the sharpest results.

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