Sharpness at 8mm

For this review, the sharpness test is carried out using a real-world subject, rather than a test-chart. For this part of the test, the AF-S Fisheye Nikkor 8-15mm f/3.5-4.5E ED Lens was attached to a Nikon D810, which in turn was secured to a sturdy tripod. Any variances in light and tone are due to natural changes in light during the session.

The full frame at 8mm

Sharpness is very good at wide open, getting a little softer as you move through the aperture stops. It becomes particularly soft once you reach f/16, and softer again at f/22. The best results are found between f/5.6 and f/11. Edge sharpness is reasonably good all the way up to f/16 and f/22, where it softens a little.

Aperture	Centre Crop	Edge Crop
f/3.5
f/4
f/5.6
f/8
f/11
f/16
f/22