Digital cameras make photography easy and fun. They are as simple to use as traditional point-and-shoots, but have added features such as exposure adjustment, special effects, video recording capabilities, and clear, bright LCD screens that let you preview your picture before you take it and let you see it at your disposal.

With a digital camera you can take unlimited pictures and not worry about running out of film--just download your photos to a computer, and your camera's memory is free again. Improvements in digital storage allow you to take up to 1000 pictures on certain memory cards. In addition, you never have to pay for film processing, and you get your photos immediately, instead of having to wait for the prints to be developed. You can e-mail photos to friends, print them out on photo paper or stickers, or post them on the Web, all without hassling with photo labs or scanners.

When shopping for a digital camera, start by identifying your needs. Do you want to take pictures of friends, family and landscapes? Will you be using the camera for professional graphics work? Are you going to be editing your pictures? Do you ever plan on printing your photos? 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. Check out the specific features below for more details.

Ambient light: The natural light in a scene.

Anti-Shake or Image Stabilization: Minimizes the effect of camera shake by eliminating the blur to deliver clean and crisp images every time.

Aperture: A small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera's sensor as a picture is taken. The aperture diameter is expressed in f-stops; the lower the number, the larger the aperture. For instance, the aperture opening when set to f/2.8 is larger than at f/8. The aperture and shutter speed together control the total amount of light reaching the sensor. A larger aperture passes more light through to the sensor. Many cameras have an aperture priority mode that allows you to adjust the aperture to your own liking. (Also see "Shutter Speed" below).

CCD: Charge Coupled Device: one of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the camera's lens. Each of the thousands or millions of tiny pixels that make up the CCD convert this light into electrons. The number of electrons, usually described as the pixel's accumulated charge, is measured, then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.

CD-R: CD-Recordable: a compact disc that holds either 650 or 700 MB of digital information, including digital photos. Creating one is commonly referred to as burning a CD. A CD-R disc can only be written to once, and is an ideal storage medium for original digital photos.

CD-RW: CD-Rewritable: similar in virtually all respects to a CD-R, except that a CD-RW disc can be written and erased many times. This makes them best suited to many backup tasks, but not for long term storage of original digital photos.

CMOS: Complementary Metal-Oxide Semiconductor: one of the two main types of image sensors used in digital cameras. Its basic function is the same as that of a CCD. CMOS sensors are currently found in only a handful of digital cameras.

Compression: Another factor that affects image quality is compression, 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 also makes it faster to save and download photos and easier to e-mail photos or download them as part of a Web site. For most uses--e-mailing photos to friends, printing out photos for albums, or posting images on the Web--compressed images are adequate. Compression causes a small amount of data loss, however. If you need the absolute best-quality images, consider buying a camera that takes uncompressed photos. You'll only be able to fit a few uncompressed images on a memory card, but you'll get the sharpest, clearest, most detailed pictures possible. This feature is ideal when you plan on printing your photos.

Computer Connections: Most high-end cameras have software and connections for both Mac and PC computers, but make sure the digital camera you want is compatible with your platform before you buy it. All consumer digital cameras come with the software you need to download your pictures onto a computer. Most also include image-editing software--which lets you crop, adjust, or add special effects to your photos--and the cables and/or cards you need to connect to your computer. Connecting and downloading pictures from a digital camera is easier than you might think; the software and cables are straightforward to install and use. Once you've downloaded and edited your images, most e-mail programs will let you attach them to messages. You can also upload them to your Web site, or copy them onto a CD to give to your friends and family, or use the printer hooked up to your computer to print pictures out. One of the advantages of using a digital camera is that you can make copies of your photos whenever you want, without having to hunt through negatives and send them out for processing at a lab. You can also make calendars, greeting cards, collages, and enlargements easily and inexpensively at home. Digital cameras can use a variety of different interfaces. Some use a USB, which plugs into a port on the back of your computer.

Contrast: The difference between the darkest and lightest areas in a photo. The greater the difference, the higher the contrast.

Digital Zoom: Enlarges just a portion of the image, and in doing so, you lose image quality because the same amount of digital information is spread over a larger area.

External Flash: A supplementary flash unit that connects to the camera with a cable, or is triggered by the light from the camera's internal flash. Many fun and creative effects can be created with external flash.

Face Detection: Technology that automatically controls focus, exposure, color, and flash to help reveal faces in shadows, make skin tones look more natural, reduce red-eye, and eliminate harsh facial glare, so your photos bring out every expression on every face in every shot.

Flash: Most digital cameras come with a built-in flash. Basic flash modes should include automatic (senses when to use the flash according to lighting conditions), on (for all photos), and off. 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 fires a series of short flashes before the final flash and exposure, making your subject's pupils contract and preventing them from having glowing red eyes in the final photo. Night portrait mode sets your flash to go off at the beginning or end of a long exposure, letting you take portraits set against a night scene, such as a cityscape. However, you should find something steady to set the camera on, since the long exposure needed for low light will turn any shake of the camera into a blurry spot in your image.

Focus and Exposure: Fixed-focus digital cameras have a lens that is preset to focus at a certain range. Higher-end digital cameras usually have auto focus instead, which automatically focuses the camera at your subject's distance. Most cameras automatically determine the correct exposure for the lighting conditions. Sometimes, however, the scene will appear too dark or too washed-out. In these cases, it's handy to have a digital camera that offers manual exposure adjustment, allowing you to set the exposure a few stops brighter or darker. A digital camera's ISO-equivalent rating lets you know how light sensitive it is; a camera rated ISO 100, for example, has about the same light sensitivity as a traditional film camera loaded with ISO 100 film. Higher ISO ratings mean the camera is more sensitive to light and can take pictures in darker settings. Digital cameras 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.

Image Browser: An application that enables you to view digital photos. Some browsers also allow you to rename files, convert photos from one file format to another, add text descriptions, and more.

Image Editor: A computer program that enables you to adjust a photo to improve its appearance. With image editing software, you can darken or lighten a photo, rotate it, adjust its contrast, crop out extraneous detail, remove red-eye and more.

Image Resolution: The number of pixels in a digital photo is commonly referred to as its image resolution.

ISO Speed: A rating of a film's sensitivity to light. Though digital cameras don't use film, they have adopted the same rating system for describing the sensitivity of the camera's imaging sensor. Digital cameras often include a control for adjusting the ISO speed. Some will adjust it automatically depending on the lighting conditions, adjusting it upwards as the available light dims. Generally, as ISO speed climbs, image quality drops.

JPEG: A standard for compressing image data developed by the Joint Photographic Experts Group, hence the name JPEG. Strictly speaking, JPEG is not a file format, it's a compression method that is used within a file format, such as the EXIF-JPEG format common to digital cameras. It is referred to as a lossy format, which means some quality is lost in achieving JPEG's high compression rates. Usually, if a high-quality, low-compression JPEG setting is chosen on a digital camera, the loss of quality is not detectable to the eye.

LCD: Liquid Crystal Display: a low-power monitor often used on the top and/or rear of a digital camera to display settings or the photo itself.

LCD Viewfinders: Some digital cameras come with at least an optical viewfinder--the kind you look through on traditional film cameras--as well as an LCD screen built into the back, which you can use as a viewfinder as well. The LCD screen is especially useful because 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. However, using the LCD screen can be a significant battery drain.

Lens: The length of a camera's lens determines how much of a scene will fit in a picture. Lens lengths vary between wide-angle (used for landscapes and shots in which you want to include as much as possible) and telephoto (used for close-ups and to zoom in on faraway objects). "Normal" lenses, about 50mm on traditional cameras, most closely approximate what your eye sees; anything shorter than 50mm is considered wide-angle, while anything longer is usually considered telephoto. The image sensor in digital cameras is smaller than 35mm film, so lenses on digital cameras tend to be much shorter than on traditional cameras. Look for the "35mm equivalent" rating to get a better idea of your camera's range. Most fixed-length lenses on digital cameras fall somewhere between wide-angle and normal focal length. Many digital cameras now offer zoom lenses, which take you from wide-angle to telephoto. In addition to this optical zoom capability, some cameras provide digital zoom, which enlarges an area in the picture. While digital zoom adds extra close-up power, image quality may suffer at a very high magnification. Some cameras also have macro capability, which lets you focus very close and take pictures of small objects.

Lithium-Ion batteries allow greater recording time than NiMh batteries. Not only will Lithium-Ion batteries hold a longer charge, they also have a longer shelf life, generally 5-7 years. Lithium-Ion batteries also have no "memory effect" and will show down to the minute, the remaining life of the charge so you won't be surprised at the worst time that you have a dead battery. Lithium-Ion also allows the battery to be charged in the camera.

Media: Material that information is written to and stored on. Digital photography storage media includes SD Cards, XD Cards, and Memory Stick Duos.

Megabyte (MB): A measurement of data storage equal to 1024 kilobytes (KB).

Megapixel: Equal to one million pixels.

Memory and Image Capacity: Memory, the equivalent of film in a conventional camera, is where pictures are stored as you take them. 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. But if you plan on taking many pictures without having access to your computer for downloading, you should buy a camera with a lot of included or expandable memory--or buy extra memory media. Cameras with internal memory store their images in a nonremovable memory chip embedded within the camera. However, most consumer cameras use external memory that you can remove when it's full. You can increase the number of photos you can take by buying additional external memory.

Memory Stick Duo®: A memory card slightly smaller than a single stick of chewing gum. Like SD and XD, it is flash-based storage for your photos. In addition to shooting photos, many digital cameras will allow you to shoot short video clips. Although they are limited to just a couple minutes, they are perfect for capturing a moment when a photo just won't be enough. Memory cards will not only store photos, but they will also store video. Just as you can store more pictures with a higher capacity card, you can also shoot more video with higher capacity memory card. Available in sizes up to 16GB depending on camera.

Modes:

• Automatic Mode: Camera uses its best judgment to select shutter speed, aperture, ISO, white balance, focus and flash to take the best shot possible. However, this mode is not fool proof.
  
• Portrait Mode: Applies maximum aperture to bring the person into focus while allowing the background to fall out of focus.
  
• Macro Mode: Displays a magnified image on the LCD in macro focus shooting, suppressing flash to avoid saturated whites.
  
• Landscape Mode: Reproduces the atmosphere of the entire landscape. Captures saturated blues and greens.
  
• Sports Mode: Uses a fast shutter speed to produce a clear picture of fast moving subjects.
  
• Night Mode: Slow shutter speed reproduces the mellow atmosphere of a night scene beautifully.
  
• Movie Mode: Feature that allows you to use the camera as a video camera to record movie files. Some cameras also allow for movies with sound.
  
• Smile Shutter Mode: Also known as Kids and Pets Mode, this mode speeds up shutter speed and helps reduce shutter lag with some pre-focusing.

Optical Zoom: Uses the lens of the camera to bring the subject into closer view. When compared to digital zoom, optical zoom is far superior since you do not lose image quality like you do with digital zoom. 3x-5x optical zoom is standard.

Picbridge: Feature becoming a standard in cameras, this element allows for easy connection between a camera and computer via a USB cable.

Pixel: (short for Picture Element): Digital photographs are comprised of thousands or millions of them; they are the building blocks of a digital photo. The more pixels a camera features, the more details your photos will contain and the picture will be clearer.

Power Source: Digital cameras use significantly more power than traditional cameras. While typical cameras usually need their batteries replaced every 15 rolls of film or so, you might find your digital camera running out of batteries before you've filled its memory (especially if it runs on AAs). Digital cameras use either a rechargeable battery pack or traditional batteries, and some come with an AC adapter as well. Consider buying an extra battery pack or investing in rechargeable AAs, and always have extra on hand. The biggest drawback to digital cameras is their tendency to run out of power in the middle of a photo shoot.

Price Range: The first digital cameras were meant for professionals and cost more than $10,000. But current technology makes it possible for manufacturers to offer high-resolution, full-featured digital cameras at a price many consumers can afford. Today's digital cameras run anywhere from $99 to more than $1,500, depending on resolution and features. While the initial expense of a digital camera is still higher than a traditional point-and-shoot, you may find that the added convenience and savings in film and processing costs are worth it.

Red-eye: The red glow from a subject's eyes caused by light from a flash reflecting off the blood vessels behind the retina in the eye. The effect is most common when light levels are low, outdoors at night, or indoors in a dimly lit room.

Resolution: Maximum resolution is one of the most important ratings of a digital camera. Resolution refers to how many pixels make up a photo, and it is usually measured in the horizontal by vertical resolution, as in "1280 x 960." The higher the resolution, the sharper the picture. Common digital-camera resolutions include 1600 x 1200, 1280 x 960, and 1024 x 768 (termed "megapixel" resolutions), 640 x 480, and 320 x 240. Most cameras offer a choice of resolutions, since high-resolution pictures take up much more memory. The resolution you need depends on what you plan to do with your photos. If you just want to e-mail photos to your friends or put them on the Web, you'll be happy with a lower resolution like 640 x 480. If you want to print your photos, however, megapixel resolutions will give you better results, because most printers print at 600 dots per inch. Lower-resolution printouts tend to be grainy. Megapixel cameras often offer the option of taking lower-resolution photos so that you can fit more photos in the camera's memory.

SD Cards: Most common form of memory card used by Canon, Nikon, Samsung, and Panasonic. Most new SLR's use this type of memory storage.

Self-Timer: A self-timer lets you set your digital camera for a delayed exposure, usually giving you about 10 seconds before it takes the picture. This feature is useful for getting yourself in the photo and can also be used to take low-light photos, preventing the camera shake caused by pushing the exposure button.

Sharpness: The clarity of detail in a photo.

Shutter Speed: The camera's shutter speed is a measurement of how long its shutter remains open as the picture is taken. The slower the shutter speed, the longer the exposure time. When the shutter speed is set to 1/125 or simply 125, this means that the shutter will be open for exactly 1/125th of one second. The shutter speed and aperture together control the total amount of light reaching the sensor. Some digital cameras have a shutter priority mode that allows you to set the shutter speed to your liking. (Also see "Aperture"). An essential part of photography, "exposure" determines the amount of incoming light that reaches the CCD. Skilled Photographers know how to use aperture and shutter speed to achieve creative effects. Different scene modes will help optimize the camera's auto exposure system, achieving ideal results for many popular shooting situations. The result is the perfect picture every time.

SLR: Single lens reflex camera. Mostly used by professionals. A main advantage is faster shutter speeds for fast action shots. You can also outfit the camera with different lenses depending on the atmosphere of the shot.

Super Zoom: Point and shoot camera with zooms in the range of x10 to x20.

Thumbnail: A small version of a photo. Image browsers commonly display thumbnails of photos several or even dozens at a time. In Windows XP's My Pictures, you can view thumbnails of photos in both the Thumbnails and Filmstrip view modes.

TV Connections: Some digital cameras include a "video out" function that gives you the option to hook them up to a TV to display your pictures. With this feature you can also record your pictures onto a VHS tape or a CD.

USB: Universal Serial Bus: a protocol for transferring data to and from digital devices. Many digital cameras and memory card readers connect to the USB port on a computer. USB card readers are typically faster than cameras or readers that connect to the serial port

XD Card: The type of memory card used by Olympus.

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