Photographed using a Sigma DP1 camera.
Most compacts use smaller CCD or CMOS sensors (usually 7-9.5mm diagonally) whose pixels are just 2-3 microns wide, and use a striped or Bayer-pattern RGB filter array to help create a color image from black-and-white-sensitive pixels. At 24.9mm diagonally, the DP1’s Foveon X3 Direct Image sensor measures far larger than most compact camera sensors. It also boasts 7.8-micron pixels (typical of 8-10MP DSLRs). Cameras with larger pixels tend to be more sensitive to light and have better noise performance at higher ISOs.
In addition, Foveon X3 sensors use a three-layered approach to capturing red, green, and blue information from a scene, similar to the layers in color film. In the DP1, each layer contains an array of 1768×2652 pixels (4.7MP), which Sigma and Foveon add together for 14.1MP. Claiming the DP1 has a 14.1MP sensor is controversial, since it’s not in keeping with certain industry standards, such as CIPA’s Effective Pixel rules, which would put it at 4.7MP.