The MegaPixel (MP) Rating of a Digital Camera

The resolution of a digital camera is perceived to be proportional to its pixel count. A digital image is nothing but a continuous arrangement of pixels or picture elements. Resolution is expressed as the number of horizontal pixels multiplied by the number of vertical pixels (E.g. 1600x1200 => 1.92 MP). Digital cameras record visual image with the help of CCD or CMOS sensors and each pixel of the output image on screen will map to a specific pixel on the image sensor in the digital camera.

Digital Camera Resolution Formula MegapixelDigital Camera CCD CMOS PixelMegapixel Resolution Myth

In order to improve the resolution, one tends to simply increase the pixel count. The more the number of pixels the more details the image will provide and the more it will resemble to the real world image. But for a given image or sensor area, increasing the number of pixels tends to saturate at a certain point and further increase in pixels doesn't mean much to the human eye. A common man will not be able to accurately identify the difference in quality of a usual 10cm x 15cm photograph taken by digital cameras having resolution greater than 5 MP. But higher pixel count will be beneficial only when you are trying to generate a bigger picture from a smaller one or when you are trying to crop a particular portion of the picture and try to enlarge it.

There are some common misinterpretations of resolution which a camera manufacturer might try to exploit. Since resolution is more like a square function (length x height), gain in pixel count will not be directly related to resolution gain. Also some pixels on a digital camera sensor will be used for other compensation mechanisms and not really for capturing the image. Companies may include this overhead in order to bump up the pixel rating. In color displays such as LCD screens, subpixel rendering is used in which a single pixel will be composed of a three sub pixels (R, G & B) and so the pixel count should never be exaggerated. The size of the camera sensor also plays a part in deciding resolution, sharpness and image quality for digital cameras having the same pixel rating apart from other factors like lens quality, sensitivity of the image sensors, optical zoom capability, shutter speed, etc.