Sigma 14mm f/1.8 DG HSM Art Aperture Series: Focus Stacking Versus Single Frame
See my Nikon wish list and get Sigma 14mm f/1.8 DG HSM Art at B&H Photo.
The Sigma 14/1.8 is an outstanding lens with corner to corner sharpness, but focus stacking might be necessary to get the best out of it with near-to-far compositions, as here.
This page shows 3 exposures of the same scene, all at f/10: near focus (on the aspen trees), far focus, and a 2-frame focus stack. Discussion is about what is gained from the stack and how it addresses the challenges of lens performance (field curvature in particular) and depth of field.
Sigma 14mm f/1.8 DG HSM Art Focus Stacking: Two Aspen at Beaver Pond, Sunset
Includes images up to full camera resolution, and crops.