"PeterN" wrote:

Ohh... Unless you typically mount f/1.4 lenses and shoot
focus chart wide open, there isn't a focus problem. If
you do shoot charts, there might be.


I am leaning towards the D4 because of its better high ISO usability and
higher fps rate. Although it has less pixels than the D800, the pixels
are much larger.


That's probably the wrong way to think about it. If you look at the prints,
the apparent noise in the print (even for smaller prints) will be more a
function of the total sensor area than how that area is divided into pixels.
Both sensors are capturing the same total number of photons for the same
scene.

Obviously, four small pixels have four times as much circuit noise as one
fat pixel, but you can get the effect of pixel binning by applying stronger
noise reduction to the higher pixel count sensor, and the circuit noise is
pretty small compared to the shot noise at high ISO.

-- David J. Littleboy
Tokyo, Japan