Resolution
at f16
Nikon
15mm f3.5 AIS v Sigma 12-24mm f3.5-4.5
100%
Crops (f16) Centre image circle
|
|
Nikon
15mm / f16 |
Sigma
12-24mm / 15mm
/ f16 |
Pretty
much a repeat of the f11 picture here; neither shows significant diffraction
softening by stopping down from f11: for all the difference it makes,
centre frame resolution for these lenses peaks at f8.
100%
Crops (f16) extreme upper right corner
|
|
Nikon
15mm / f16 |
Sigma
12-24mm / 15mm / f16 |
Unsurprisingly,
extreme corner crops show the benefit of stopping down this far - the
Sigma even more evidently than the Nikon 15mm, which still doesn't
deliver enough information at f16. For critical work, f16
is the only really useable aperture on the Sigma 12-24mm, but here
it is quite serviceable.