Choosing a digital camera doesn't have to be difficult. The key is knowing what you want to do with the photographs it creates.

Digital camera advertisements all push megapixels and for good reason. At the heart of every digital camera is an electronic sensor or CCD that records the image. The sensor is composed of thousands of microscopic dots called picture elements, or "pixels" for short (''pix'' for picture, "el" for elements). The more pixels an image has the better its resolution, and the more detail it will have.

Simply put a megapixel is a million pixels. A one-megapixel digital camera, at its maximum quality setting, produces images composed of approximately 1,000,000 individual pixels. This is also described by an equation showing the amount of pixels laid out horizontally and vertically on the CCD. For example a camera with 1152 x 864 pixels means it has 995,328 pixels. Similarly, a two-megapixel camera will usually have a spec of 1600 x 1200 (1,920,000 pixels), and so on.

Why is this important? Resolution is important because to get large images that equal conventional photo print quality you need a certain amount of pixels. Otherwise, your pictures will become jaggedy or pixelated. So in determining how many pixels you need, you first have to decide what size prints you want to make.

The rule of thumb for printing digital images is that you need 300 dpi (dots per inch) for top image quality. So for example, you want to print 5 x 7's you would need something in the area of a 3.3 megapixel camera. And if you're very careful, you can actually print larger images by increasing the size of the files through software. So depending on your personal standards--what one viewer considers fine, another might find unacceptable--a good 8 x 10-inch print can come from a two-, three-, or four-megapixel file.

Now the other side of this, maybe you just want to take pictures for posting on the Web, to put on CDs, or E-mail to friends. There your requirements would be much lower. For the Web you only need 72 dpi-a full 75 percent less resolution than for a high quality print. So obviously, you'd be able to get away almost exclusively with a 2-megapixel camera. Incidentally, if you want all the options (shoot high and low quality), you should look for a camera that offers several different shooting resolutions. This way you won't lock yourself into shooting 5mb files when all you need is 1mb.

When you are in the upper deck of a ballgame, nothing comes in more handy than a good zoom lens. Nine out of ten cameras today come with a zoom, and the only reason not to get a camera with a zoom lens would be cost. So when you look for a camera with a zoom, the only thing you have make sure is that the lens is an optical zoom and not a digital zoom. Optical zooms let you change the focal length just like conventional 35mm zoom lenses. A digital zoom though, takes a smaller image captured on the CCD crops it and then enlarges it (basically by duplicating every pixel).