Distortion & Aberration

Distortion/Vignetting (f5.6)
Rollover the Sigma 12-24mm image (below) to reveal one made by the Nikon 15mm AIS.

Nikon 15mm v Sigma 12-24mm Distortion Test

Respect due to both lenses for outstanding geometry. The eagle-eyed may spot a whisper of waveform distortion in the Nikon 15mm and the merest trace of barrel distortion from the Sigma 12-24mm, but these are very minor quibbles. How – and why – Nikon ‘updated’ this lens to endow it with such horrendous waveform distortion is a mystery.

Impressive, too, is the lack of vignetting: the Sigma frame isn’t as evenly illuminated as the Nikon 14mm’s, but neither are problematic.

 

100% Crops (window detail / f11)

Nikon 15mm / f11
Sigma 12-24mm / 15mm / f11

A rectilinear object in the frame corner reveals that suggestion of waveform distortion in the Nikon shot, as well as some chromatic aberration. The Sigma 12-24mm is unimpeachable on both counts.

200% Enlargements showing aberrations (corner)

Nikon 15mm / f11 Sigma 12-24mm / 15mm / f11