Sharpness at 50mm

For these sharpness tests the Fujifilm XF 16-50mm F4 R OIS WR lens was attached to a Fujifilm X-T3 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 50mm

The centre is a little soft wide open at f/4, with peak performance achieved in the f/5.6-f/11 range. Diffraction sets in at around f/16, with its effects becoming more visible at f/22. The edges are also a little soft wide-open at f/4, with the f/5.6-f/11 range being the optimum setting.

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