Sharpness at 14mm

For these sharpness tests the Nikon 10-20mm lens was attached to a Nikon D500 camera 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 100% crops represent about 1/500th of the total frame area.

The full frame at 14mm

At the 14mm setting, the image centre is impressively sharp wide open. Similarly to the 10mm setting, the effects of diffraction start to be visible already at f/8, with the smaller apertures being progressively more strongly affected.

The edges are a bit softer and quite heavily affected by chromatic aberrations, which also interfere with image sharpness. The best results are achieved at f/8 and f11. The f16 setting is usable, but the f22 setting is best avoided unless you really need it for maximum depth of field.

Aperture	Centre Crop	Edge Crop
f/5
f/8
f/11
f/16
f/22