Digital Commons at Penn State

The medium defines the ways you can transfer images from the camera to the computer. You can either connect the camera directly to a computer using a cable or you can remove the card or disk from the camera and pop it into a special drive. After downloading the images, erase the camera's storage medium, and you're ready to take more pictures.

This varies with each camera according to its memory capacity. It is also a factor of the resolution that the camera was set to when each photo was taken. Higher resolution photos will take up more space on the camera's memory. The Sony CD Mavica, for example, can use a CD-RW disc which can store up to 1,000 images and be used over and over. Other cameras use various memory formats to store up to several thousand images.

To put it simply, the photo was taken at a high resolution setting on the camera. When you open it in an application such as Photoshop, it may look pretty large -- you may even have to scroll to see the whole photo. The file's physical dimensions, however, may only be something like 3"x5", which is what the printer will output. A lower resolution setting will result in a smaller size on the monitor, but the same physical size when the photo prints. Its quality will not be as good as a photo taken at a higher resolution setting, however.

An image's resolution is measured in dots per inch, or pixels per inch in the digital realm. Since a monitor never displays more than 72 dpi (dots per inch), photos that will never be used in print (such as for the Web or PowerPoint) are better saved down to 72 dpi from higher resolutions. You'll have a smaller file size and the files will load more quickly.

To see a file's physical size and resolution, open it in Photoshop and under the "Image" menu, go to "Image Size...". It will bring up a window that will allow you to view and adjust the photo's physical size and resolution.

Identify what you want to do with your photographs. Will they be shared with family and friends, used professionally in a magazine or the Web, or needed at work or school? What image quality do you need? What are you going to photograph? Close-ups, action, or long-distance? How experienced are you? Do you want automatic settings or control over your camera's functions?

There are five categories of digital cameras:

• Entry-level -- Basic digital cameras with few features and limited image quality. Priced from $50-$200.
• Deluxe point-and-shoot -- These cameras offer more controls and produce better images than entry-level ones do. Priced from $200-$400. Printing is limited to 4x6 inches.
• Professional lite -- Features, quality, and ease of use make these cameras ideal for many different jobs, ranging from graphic and Web design to insurance and real estate. Priced from $300-$800.
• Professional -- The best of digital cameras, producing images that meet or exceed the quality of film. Priced from $1500-$60,000.
• Gadget -- Toy cameras, and cameras that are built into computers. Priced from $10-$200.

The major feature that separates this camera from point-and-shoot cameras is the amount of picture information it captures. Inside every digital camera is a chip that captures the picture. In this group of cameras, the quality and size of that chip increases. These cameras have very accurate and detailed chips, some that even rival the quality of film. Many of these cameras offer manual and automatic exposure control, and include an optical zoom lens, LCD screen, and flash sync connection.

Digital cameras store images as a collection of tiny dots called pixels. The more pixels, the better the quality. The number of pixels captured by the image sensor is known as resolution. Resolution refers to the number of pixels packed into a certain area. Megapixel cameras capture one million pixels or more. The resolution of consumer grade 35mm film is estimated at about 6 million pixels.