Real-world samples from the Nikon-mount Sigma 18-35mm F1.8 DC HSM

“the reason I’ve shot subjects with fore-aft separation is to make it clearer what is and isn’t in focus”

Considering what I previously said, what’s left is a function of aperture setting and sensor size, not AF performance.

“The camera does record which AF point was used in the file’s EXIF, so I may be able to check if you want to know, for any given image…”

That’s not a practical or feasible thing to do and not something I would ask or expect you to do. What would be practical and feasible, for the reasons you said you took the pictures, and otherwise, is what I suggested, subjects at different distances with subject matter that is essentially flat in distance to each other.

Just offering some constructive criticism. You have to understand that you are producing a product for others. A chef that says he’s OK with some crab shell in a crab dish doesn’t mean most people are willing to eat such a thing. I saw that on Chopped. And yes, that chef got chopped, and rightly so.

Source Article from http://www.dpreview.com/news/2013/10/11/sigma-usa-announces-18-35mm-f1-8-dc-art-for-nikon