This MOD (Minimum Object Distance) series from f/4 through f/16 evaluates sharpness, depth of field, and especially secondary color correction.
Fujifilm GF 250mm f/4 R LM OIS WR Aperture Series: Headlight Closeup (Fujifilm GFX-50R)
Includes up to full camera resolution from f/4 through f/16.
f10 @ 1/25 sec, ISO 100; 2018-12-17 15:06:42[low-res image for bot]
GFX 50R + Fujifilm GF 250mm f/4 OIS R WR @ 198mm equiv (250mm)
ENV: Lundy Lake, altitude 6000 ft / 1829 m
RAW: LACA corrected