You will often hear the term resolution referred to when comparing video products, so let's have a look at what it means:
The most common method of stating resolution is to refer to it in pixel values e.g. 640 X 480.
The first value indicates the number of pixels across the image width, and the second value indicates the number of pixels in the image height.
Straight away you will be able to see that this method of expressing resolution also indicates the picture format. The two most common formats are 4:3 and 16:9 (or widescreen).
If you divide the first value in the example above (640) by 4 you get the result = 160; multiply this by 3 and you can confirm that such an image will be presented in the standard 4:3 format.
Essentially, the more pixels the better!
Despite what you may have seen on TV Spooks and Spy programs it is not possible to zoom-in, enhance, or enlarge images to uncover data that was never seen by the camera.
You need to bear in mind that this number of pixels is all you have to interpret your real world scene. So, if you fit a lens to a camera with an imaging device that has 640 pixels across the chip and set it up to view an image 6.4m wide, you will have only 1 pixel per cm. Believe me, the resultant image will be virtually useless.