The Nikon D3S is a 12.1-megapixel professional-grade full frame (35mm) digital single-lens reflex camera (DSLR) announced by Nikon Corporation on 14 October 2009. The D3S is the fourth camera in Nikon's line to feature a full-frame sensor, following the D3, D700 and D3X. It is also Nikon's first full-frame camera to feature HD (720p/30) video recording. While it retains the same number of pixels as its predecessor, the imaging sensor has been completely redesigned. Nikon claims improved ultra-high image sensor sensitivity with up to ISO 102400, HD movie capability for extremely low-lit situations, image sensor cleaning, optimized workflow speed, improved autofocus and metering, enhanced built-in RAW processor, quiet shutter-release mode, up to 4,200 frames per battery charge and other changes compared with the D3. It was replaced by the D4 as Nikon's high speed flagship DSLR.