Upload & Sell: On
Thanks for the responses, guys. I know that the "ideal" performance would be that all AF points would produce identical results, but I'm not living in an "ideal" world.
BV, I'm not sure that I understand the point of your test procedure. Doing your test at 24mm would seem to require either a very large target or that the camera be extremely close to the target, or a combination of both. Plus, it doesn't mirror what I do when I'm actually taking photos.
When I'm taking photos with the outer points, my intent is to move the subject to the outer parts of the frame and have the sharpness on the subject there, under the AF point, not at the center of the frame.
I realize that different lenses can produce different results that way, but if an AF point is wonky, it should be easy to determine, in spite of the lens utilized. Since my initial post, I repeated the tests with the Nikon 28-70 f/2.8 AF-S and 35-70 f/2.8d. Both lenses produced almost identical results to the first test that was done with the 24-70, in that the center AF point photo was slightly sharper than either of the 2 extreme outer AF point shots.
But, I'm always willing to learn, so anyone that can help me understand a better way of doing these AF tests, I'd be grateful.