>What does the 57% crop mean ? that it was taken in DX mode ?

He's trying to apply the same level of magnification to both the D700 & D800 images, which requires some downsampling of the D800 images.

Some may find that makes for an unsatisfying test, but in the context of comparing output of both cameras at an identical print size, it's appropriate. For those hoping the higher D800 pixel density allows them to print larger, it doesn't provide much info. But, it looks like you can be confident the D800 isn't a step backwards from D700 in terms of low-light shooting, which is something some people feared.

Larry - a Bay Area Nikonian
My Nikonians gallery

www.tempered-light.com