Aberration
and Distortion
Nikon
15mm f3.5 AIS v Sigma 12-24mm f3.5-4.5
Distortion/Vignetting
(f5.6)
Rollover
the Sigma 12-24mm image (below) to reveal one made by the Nikon 15mm
AIS.
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 |
