In fact, the algorithms that have been used by the AF system have been specially refined for a greater degree of accuracy and versatility, where the autofocus itself has been initiated faster, allowing it to keep pace with the intended subject. Single-point AF, Dynamic-area AF, 3D-tracking, and Auto-area AF will be joined by a fifth AF-area mode that is simply known as Group-area AF, where it relies on 5 focus points. This opens the door to smoother autofocusing as well as a faster workflow.
Sporting a new EXPEED 4 image-processing engine, a new Nikon FX-format CMOS image sensor that does 16.2MP photos, ISO 100 to ISO 25600, as well as support for extended sensitivities as low as the equivalent of ISO 50 and as high as the equivalent of ISO 409600, the Nikon D4S is not going to come cheap at $6,500 a pop when it arrives later this March 6th. Looks like rumors of an end February announcement for the Nikon D4S were spot on.