Resolution (f16)

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.