Sharpness at 400mm

For these sharpness tests the Fujifilm XF 100-400mm F4.5-5.6 R LM OIS WR lens was attached to a Fujifilm X-Pro2 body, which in turn was mounted on a sturdy tripod and triggered with a remote release cable. Slight tonal changes are due to slight changes in natural light during the session.

The full frame at 400mm

At 400mm both the centre and the edges are a little soft wide open, with peak performance achieved in the f/8-f/16 range. Diffraction sets in at f/22.

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