The New Horizons science payoad consists of seven instruments, three optical instruments, two plasma instruments, a dust sensor and a radio science receiver/radiometer. The payload was designed to investigate the global geology, surface composition and temperature, and the atmospheric pressure, temperature and escape rate of Pluto and its moons. The payload is incredibly power efficient—with the instruments collectively drawing less than 28 watts—and represents a degree of miniaturization that is unprecedented in planetary exploration. The instruments were designed specifically to handle the cold conditions and low light levels at Pluto and the Kuiper Belt beyond. If you want to know the key data--including mass, average power, development engineers, and a bit about the funcationality on the instruments including Alice, REX, Ralph, LORRI, SWAP, PEPSSI and the Student Dust Collector here's MORE@Johns Hopkins
If you want to know more specifically about the color-camera called Ralph (the one responsible for the tan- and sepia-toned images) here's an interview with the lead engineer for that camera. Joseph Stromborg at VOX described it as "putting a GoPro on a speeding bullet".