Pixel and MegaPixel

What exactly is a pixel? Why should you care?

First, a definition. Pixel is short for "Picture Element" which is the smallest part of a digital camera sensor. When you take a digital picture, the image that is saved is made up of individual pixels of varying color and shade. Groupings of these pixels is what actually makes up the image itself.

As an example, let's take an image of a building. The image itself is made up of a large number of individual color squares. If you zoom into a portion of the image, you can begin to see the rough shapes of the individual colors. Fully increasing the image size, you can actually see each color square. These colored boxes are Pixels. The size of a digital camera's sensor depicts the number of pixels that can be captured when it records the image. This is represented as "MegaPixel" or Millions of Pixels. The larger the rating, the greater the amount of "Picture Elements" is picked up via the sensor

when an image is taken. It should be noted that the higher the pixel rating, the larger the digital image will be (in width x height and the amount of space needed for storage).

Great, so what does having a larger pixel size allow?
In general, the number of pixels can effect the size or enlargement capabilities of a photo. As a "rule of thumb", the following lists maximum picture sizes based upon the number of megapixels within an image:

* 1 MegaPixel = 5x7 maximum
* 2 MegaPixel = 8x10 maximum
* 3 MegaPixel = 11x14 maximum
* 4 MegaPixel = 20x30 maximum

If I only want to print 5x7 images, why purchase a higher megapixel camera?
Since a large number of digital camera owners utilize a computer for transferring and manipulating images, having a image with greater pixel depth and larger sizes can allow for more flexability. Scaling down a photo image can also enhance the picture quality.

To further understand pixel and picture quality, see our Resolution tutorial