<p>I use the 24-70 on a D800, and it is capable of pretty sharp results to the edges at all focal lengths when used at around f/9 in my experience, as a previous poster also mentioned. However, for distance scenes like the one you posted where large depth of field is not that important, I always focus manually, and sometimes bracket focus to get the best results. This lens DOES have field curvature, and any slight mis-focus can result in either the sharp center with blurry edges, or blurry center with sharp edges. I use the viewfinder in-focus lights as a rough guide, but prefer to trust my own eyes. I definitely can't get flat field with this lens at f/7.1 or wider, but sometimes sacrifice a bit of edge sharpness to get the greater definition towards the center that the wider apertures can provide. If after manually bracketing focus at f/9 you still can't get the edges sharp, then you should have the lens adjusted. If you like to use AF and can get sharp shots with manual focus bracketing, then perhaps a slight front or back focus AF adjustment will get your lens focusing at a point where the field curvature is eliminated.</p>