Complementary Metal Oxide Semi-conductor (CMOS) is a type of light sensor that is used by manufacturers as an alternative to the more wide spread Charge-Coupled Device (CCD) sensor types. In very broad terms CCD sensor types exhibit a higher power consumption compared with CMOS designs, but conversely CMOS sensor have an inherently higher electronic noise level. However, in truth digital imaging technology is advancing so fast that such differences are becoming blurred so much so that a manufacturer will use whichever sensor type they deem most appropriate for their camera design.
To date Nikon have used CCD sensors in their D-SLR cameras, with the exception of the D2H model, which uses a hybrid CMOS sensor of their own design known as the Joint Field-Effect Transistor (JFET) Lateral Buried Charge Accumulator and Sensing Transistor array (LBCAST) imaging sensor. The JEFET portion refers to the very low power consumption characteristics of this particular sensor type, and the LBCAST refers to the way in which it accumulates and stores image data. The D2X was the first Nikon D-SLR to use a standard CMOS type sensor.