Thanks for the feedback. Dennis, good to know I'm not losing my marbles here. Paul, you are absolutely correct. f/7.1 is the sharpest. I've been shooting my Real Estate images using a tripod, cable release, live view (for more accurate sensor focus and no mirror slap) at ISO 100 and this lens is still terrible. I've barely gotten by with some significant over processing in LR and PS. The untrained layperson doesn't see it, but myself and other pros do. I am seriously even questioning the color accuracy of this lens.
This pains me greatly (well, at least my wallet), but I think I'm going to have to move into an FX (Like a D750) and a high quality 14 - 24 f/2.8. I really do love what I'm doing in RE Photography, but these images will be the death of me before I even get this part of my business up and going.
Thanks guys.... Cheers, Marty