Digital cameras are changing photography. Digital images can be easily uploaded to your computer, manipulated using a variety of photo software and be used again and again. This year, industry experts estimate that over four million people will to make the switch from analog film cameras to digital ones.

Advantages
Since a digital camera records images on reusable memory cards instead of film, there are no developing costs, so you can take as many pictures as you want and only print the ones you like. After downloading your pictures to your computer, they’re stored as standard digital files allowing you to use your computer as a darkroom, letting you crop, enlarge and re-touch them. You can then E-mail your pictures to friends or post them on a photo-sharing Web site. If you want prints, you can use an online photo finisher or create them at home on a photo printer.

Identifying Your Needs
When shopping for a digital camera, consider the following:

Will you primarily be viewing your pictures on a computer screen or do you plan to make a lot of prints?

Will you be using the camera for professional graphics work?

Will you need a zoom lens?

Are there specific features you require, like macro ability or movie mode?

Knowing what kind of photos you'll be taking most often will help you decide what resolution, storage type, power source, and other amenities you'll need when buying a camera.

Resolution
Maximum resolution is one of the most important ratings of a digital camera. Digital images are made up of dots called pixels. The resolution of a digital camera refers to the sharpness of its pictures and is measured by how many pixels make up a photo, usually measured in the horizontal by vertical resolution. (i.e. 1280 x 960 Pixels = film resolution of 4" x 6" print). The higher the resolution, the sharper the picture. At the same time it will also mean the more memory that will be required to store an image, both in the camera and on your computer.

Memory Size
A camera's memory size will determine how many images you can store. If you anticipate downloading your images often, buying a camera with a large amount of memory isn't as important. However, if you plan to take multiple pictures before downloading them to your computer you may want to buy an extra memory card or two.

Memory Cards
Some digital cameras have a non-removable memory chip embedded within the camera for storing images. However, most consumer cameras use an external memory card than can be removed when full. Most digital cameras ship with enough memory to take from 12 to 36 shots at full resolution--about the same as one roll of film for a traditional camera. To increase this capacity or number of photos, you can buy additional external high-capacity memory cards.

Compression
This is the process that shrinks a photo's file size. Most cameras take photos as compressed JPEG files, which allows you to store more images on a memory card. Compression, or compressing images also makes it faster to save, download, email and when compressed photos are used on a Web site it decreases the amount of time it takes for a browser to load a Web page for viewing.

Power Source
Digital cameras use significantly more power than traditional cameras. A typical film camera can operate for a full year before its batteries need to be changed. However, a digital camera’s batteries may run out of power before you fill its media card, especially if you constantly use the LCD as your viewfinder. To avoid this problem consider buying an extra pack of re-chargeable batteries to have on hand, select a camera that comes with an A/C adapter, and/or buy a battery recharger.

LCD View-finders
Most digital cameras come with an optical view-finder like the ones on a regular film camera, as well as an LCD screen built into the back, which you can use as a viewfinder as well. With the LCD screen you can see what your picture will look like before you take it. It also allows you to look at the photos you've already taken. As mentioned above, using the LCD screen requires a lot of power, so use your camera’s LCD only for close-up shots.

Focus and Exposure
Fixed-focus cameras have a non-moving lens that’s preset to focus at a certain range. Moderate to high-end digital cameras usually feature auto focus, which automatically focuses the camera at your subject's distance.

Lighting
Most cameras automatically determine the correct exposure for the lighting conditions. However, there are cameras available that offer manual exposure compensation. This allows you to set the exposure a few stops brighter or darker.

Aperture Rating
Digital camera's work just like traditional cameras when it comes to aperture--the maximum aperture rating of a camera lets you know how much light it can let in. Aperture ratings represent ratios--the lower the aperture rating, the more light sensitive the camera is and the better it can take photos in low light.

Red-Eye Reduction
Some cameras include additional features, such as red-eye reduction or night portrait mode. Red-eye reduction is ideal for photographing people or animals. It works by firing a series of short flashes before the final flash and exposure, making your subjects' pupils contract and preventing them from having glowing red eyes in the final photo.

Rapid-Fire Shots
If you plan on taking pictures of subjects in motion, such as during a sporting event, you may want to buy a camera that offers "Rapid-Fire Shots." This feature allows you to take multiple pictures with one touch of the exposure button.

Special Features

Macro: this lens feature allows you to take close-up shots, usually within one foot or less and is useful for taking pictures of small objects, such as a stamp.

Mini Movie: allows you to create a short movie

Remote Control: with this feature, you can take a picture without holding the camera.