Using conventional cameras, most people maybe get five to ten "keeper" photographs out of an entire roll of film. The bad pictures — such as the one where Uncle Stu's eyes are glowing demonically red — usually end up in a shoebox in the closet. One of the many advantages of digital cameras is that they allow you to preview images, so you can print and email only those images you really like.
Digital cameras are an exciting way to capture and share images, but how do you begin to choose from all of the models and options? First of all, you need to decide what kind of resolution you need. Digital camera resolution is measured in megapixels — or one million pixels. This means that a one megapixel digital camera creates images with one million pixels, or distinct dots. As a result, an image generated by a one megapixel camera could have 1000x1000 or 2000x500 pixels, or any other dimensions that add up to one–million pixels
The megapixel rating you choose in a camera depends on the size of the images you want to print. As Dave Johnson, author of How to Do Everything with Your Digital Camera, says: "The more pixels you have, the larger your pictures can be printed." Here's quick sketch of the optimal print sizes that can be generated from images taken with digital cameras with the following megapixel ranges:
|Megapixel rating||Produces print sizes of:|
|1 to 1.9||3x5 inches|
|2 to 2.9||5x7 inches|
|3 to 3.9||8x10 inches|
|4 to 5||11x14 inches|
|6 +||13x19 inches|
Naturally, there are other important factors to weigh when purchasing a digital camera. Resolution is simply the place to start. You also need to consider zoom capability and memory size, among other things. In general, you should look for optical rather than digital zoom, says Dave Johnson, since optical zoom "actually magnifies the image, [while] a digital zoom simply grabs an array of pixels in the middle of the scene and processes them to make the image look enlarged." The result, he cautions, is that digitally zoomed images can look "pixely".