The Nikon D810 is a full-frame digital SLR that features 36.3 megapixel FX-format CMOS sensor (without an optical low-pass filter) along with Nikon's latest EXPEED 4 image processing engine. The EXPEED 4 improves performance and image quality and also offers an ISO range of 64 to 12800, which expands to 32 to 51200. There's also a new RAW Small Size option, which produces 16MP images with much smaller file sizes. The shutter mechanism has been redesigned and a first curtain electronic shutter added in order to reduce the risk of 'shutter shake'.