I agree with Tom and would add that diffraction affects are easily reduced or eliminated in post processing. I shoot scenics at f/22 frequently and after post processing the result is equal or better than the same shot at f/8.
Unlike the effects of focus problems or camera movement problems, I view diffraction as more of a contrast problem than a sharpness problem. Even at f/22, most of the little photons are getting to their proper place on the sensor and only a relative few are going off course after passing the edge of the diaphragm. The errant photons are merely diluting an otherwise good image. There is certainly some diffraction at f/8, but it is just not as noticeable.
Typically, I use Nik Tonal Contrast filter with a touch of Unsharp Mask. Then I oversharpen a bit before sending the image to my inkjet. I suspect my friends who use a D7000 would have similar results. The D800E may or may not. I will wait patiently to find out.