D4 Noise Levels - High ISO Performance

A number of claims are circulating regarding the high ISO performance of the D4 compared with the D3 and D3S, notably that the D4 offers around a one stop advantage over the D3S despite  the former's higher pixel pitch.

My own tests suggest in general terms the D4 actually offers around the same noise levels across the image as a whole as the original D3. This is by no means a poor performance, the D3 continues to be an excellent high ISO camera. So what is the basis for claiming the D4 offers a one stop advantage? Remember the D4 offers around 40% more resolution than the D3. Once the D4 images are downsampled to match the resolution of the D3, the D4 emerges as the better performer, possibly rivalling the D3S, but not exceeding it. Looking closely at the character of the noise, the D4 has more chroma noise and Capture NX2 reports the camera is always performing some noise reduction at high ISOs on NEFs, even with 'off' selected in camera. Significantly though, the D4 does have far less noise in the blue channel than the D3, meaning high ISO shots under tungsten light sources will have lower noise.

At the other end of the scale though, noise levels at lower ISOs are virtually non-existent. Overall, it looks as though Nikon has delivered its promise to produce a more rounded camera with a better balance of high ISO performance versus resolution.