Effective Pixels is a measurement of the number of pixels that actively record the photographic image within a sensor. As an example, a camera might hold a sensor containing 10.5 megapixels, but they have an effective pixel count of 10.2 megapixels. This discrepancy is due to the fact that digital imaging sensors have to dedicate a certain percentage of available pixels to establish a black reference point. These pixels are usually arranged frame-like, along the edge of the sensor, out of range of the recorded image.