So what is a megapixel?

Well the simple answer to the question "What is a megapixel" is that it is made up of one million pixels. A pixel, or picture element, is a tiny light sensor that is situated on the digital camera's CCD (coupled charged device). The CCD has taken over the job of the film, in that it captures the scene electronically to form an image, but it has the advantage of not needing to be replaced to take more pictures.

A digital camera will be said to have a certain number of megapixels. The very first cameras had less than 1 (640 x 480 pixels)! Of course the number of pixels will determine the quality of the image the camera can produce, but it is not the only thing to consider when choosing a digital camera.

The size of the CCD itself, can differ between cameras. The bigger the CCD, the more pixels it can hold. However, as it is the most expensive part of a digital camera the manufacturer would normally try to keep it as small as possible, even if that means cramming the megapixels onto it.

So how many megapixels do you need?

Now you know the answer to what is a pegapixel, we can move onto deciding how many your need. This does tend to depend on what you wish to do with your photos once you have taken them. The following table may guide you when thinking about megapixels and print sizes.

How many photos can you get on a memory card?

Most modern digital cameras allow you to choose from a number of different resolutions (the pixel count horizontally and vertically) for each shot. Just because the camera is capable of taking 10 megapixel photographs does not mean every one you take has to be at that resolution.

You are likely to be able to choose from a selection of picture sizes, such as those below.

• 640 x 480
• 1920 x 1080
• 2048 x 1536
• 3264 x 2448
• 3264 x 2176 (equivalent to 35mm film ration of 3:2)

A certain juggling act has to go on when capturing images on your camera. The greater the number of megapixels the more storage space is required for each photo. However, with today's large capacity memory cards this is less of a problem than it was a few years ago.

The next table will give you an idea of how many photographs you can fit onto different sized memory cards depending on how many megapixels your camera offers.

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