The term megapixel is a unit of measurement for the resolution ofimage sensors for digital cameras and camcorders and also for displays. For digital cameras, the resolution is specified directly in millions of pixels, in megapixels (MP). The value is calculated from the horizontal and vertical resolution. For example, a digital camera with a resolution of 2,240 x 1,680 pixels has a value of 3.76 megapixels ( photo cells).
The image size can be calculated from the number of pixels and the color depth. With 4 million pixels and a color depth of one byte (256 colors), this theoretically results in a file size of 4 megabytes( MB) without additional data. A digital photo with 10 megapixels and 24-bit resolution therefore has a file size of 30 MB.
For better comparability of the resolution of image sensors, the number of megapixels is related to the sensor size and specified in megapixels per square centimeter, whereby values of more than 40 megapixels per square centimeter are achieved. Image sensors are available with a wide variety of pixel numbers. The range for the first digital cameras was around 0.3 MP, reaching values of 15 MP and more in 2010. Professional digital cameras exceed these values many times over.