I have to make a correction to the Nikon D4 specs: the ISO sensitivity range of the D4 will be 100-12,800 and not 100-102,400 as initially reported. Sorry about that, it got lost in the translation! The ISO range will still be expandable to 50 and 204,800.
For comparison, the Nikon D3s has ISO range of 200 – 12,800, expandable to ISO 102,400.