Sharpness at 80mm

For this review, the sharpness test is carried out by photographing a real-world sample, rather than a test chart. The Neptune Convertible Art Lens System was mounted on a Nikon D4S, which was in-turn mounted on a sturdy tripod. Exposure delay was activated to prevent camera-shake. Any changes in tone you might see across the crops are due to natural light changes during the shooting session.

The full frame at 80mm

The 80mm lens yields some good sharp results at the centre, even from wide open. It is sharper from f/4, being sharpest up until f/16. At the edges, the sharpest results can be seen between f/8 and f/16. From this analysis, it’s clear that the 50mm lens provides the sharpest results of the three.

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