See my reviews of Sigma DG HSM Art lenses at 20mm, 24mm, 35mm, 50mm and more.
This aperture series from f/4 through f/11 shows how well the Sigma 12-24mm f/4 DG HSM Art handles flare into a direct intense light source along with bright clouds and deeply shadowed areas.
The ability to maintain contrast (minimize flare) is critical in such situations so that shadow areas can be opened up with detail, but not haze. It is particularly important with a camera like the Nikon D810 at ISO 64, because the camera has a tremendous dynamic range—the lens has to not limit that dynamic range (the Canon 5DS R would have been in trouble on this image)
Also treated here are field curvature and focus shift. The example is highly instructive and should prove very useful for anyone shooting the Sigma 12-24/4A.
Includes images up to 28 megapixels along with many large crops, all from f/4 through f/11.
Especially at 36MP on up, the photographer must place focus wisely for the subject matter, not just the “1/3 in” rule and not even just the near/far relationships, but also anticipating and compensating for a lens with focus shift and field curvature, which requires special care based on the shooting aperture.