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Megapixels Explained

Tulika Nair
If you don't understand the concept of megapixels, then read this information. It will tell you that this concept which is used to define resolution is not all that it has been made out to be.
Did you know that the first digital camera ever introduced, the Sony Mavica, had a resolution of only 0.3 megapixels? Today even the cheapest cameras available in the market have a resolution of at least 7 megapixels.
Several websites explain the concept but the fact remains that while heralding the importance of having a digital camera with a high number of megapixels, they tend to remain mum on the fact that it is not really the most important consideration to keep in mind while buying a camera.
Before we move on to understanding this concept, let us take a look at how megapixels are defined. The resolution of a digital camera is measured in terms of megapixels. One megapixel or 1 MP is made up of one million pixels. A single pixel is a square of color and many such pixels make up the digital images that we capture using our cameras.

The Concept
Most digital cameras have an image sensor like a CCD (Charged Couple Device) to convert light into electrical charges. Most CCDs are made of silicon which have photo detectors on them in a grid like fashion.
These photo detectors are light sensitive and measure the amount of light that strikes the diode. The charge is converted into an electrical signal and then sent to the memory chip that functions as a memory device. The total number of photo detectors on the silicon CCD defines the megapixel count of a camera.
If you want large pictures, then it would be a good idea to buy a camera that has a higher megapixel count. For example if you click a photograph with a six megapixel camera, then the maximum print size of the photo will be around A4 but with a twelve megapixel camera the photo can be printed to fit an A3 size paper.
But this is generally necessary only if you are into professional photography as the prints you will need to take will be bigger than photographs clicked for the family album. While many people believe that higher megapixels translates into better quality, this could not be further from the truth.
A user with a fleeting interest in photography does not need a camera that has a resolution of more than 3.2 megapixels.
Your average computer screen on which you view these images can show only 72 to 96 pixels per inch, so even if your camera shoots images at 1280 x 1024 pixels per inch, it will show you only 72 of those. Cameras with as low as 3 megapixels have been known to capture very clear images due to the quality of optical lens, the CCD and the size of the CCD.
In fact, the higher the number of megapixels the camera has, the more is the visual noise that is captured in your images because your sensor may not be able to comfortably handle it.
This may result in images that are not as sharp as you may expect them to be. Also, images of a larger size means that you are reducing the capacity of your memory card. It is suggested that users who use their cameras only occasionally should stick to cameras with a resolution of about 8 - 10 megapixels.
You now know that opting for a camera with high number of megapixels should not be your only deciding factor while buying a camera. And if you are still interested in purchasing a camera with a high megapixel count then there are several cameras out there that will suit your needs.