After weeks of teasing and speculation, Nikon has finally released the update to its flagship HD-SLR line. Rumored to have been used by photojournalists at the Sochi Olympics, the D4S offers advanced specs that let photographers take pictures even under severe conditions. The D4S features a new 16.2-MP FX-format CMOS sensor (with comparatively huge photodiodes for collecting light), improved autofocus and shutter speeds and supports an ISO range of up to 409,600.