I'm going to let someone else do the talking:
"I’ve spent the past 45 years involved in the analysis and design trades of spaceborne imaging systems (like the earth viewing Geoeye-1 telescope in orbit today), and Q is a wonderful, insightful and useful parameter. Q can be shown to be equal to wavelength x fno / pixel pitch. If we ignore the use of Bayer filtered pixels and do the calculation on a monochromatic basis (without a de-aliasing filter), for a Q=2 D800E (fully satisfying the Nyquist criterion at 0.55 microns), the fno turns out to be f/17.7. Thus an f/8.9 lens aperture setting on the D800E gives you a Q=1 system, which makes the D800E equivalent from a sampling standpoint to the Geoeye-1 telescope (which has a Q=0.95). In fact, many spaceborne imagers are about Q=1, which has turned out over the years to be a good compromise between resolution (NIIRS, if you are familiar with the government image quality measure) and low light performance (i.e. , SNR). And it’s interesting to note that the use of a lens set at f/8 (often the aperture that delivers the best quality image – i.e., best MTF) dovetails nicely with the achievement of a Q=1 D800E imaging camera.
So one could consider theD800E, at f/8, to be a miniature Geoeye-1 telescopic camera. The D800E has hit the traditional sweet spot for earth imaging satellite systems!"