Basic camera components

Lens
Many digital cameras are equipped with a 3X optical zoom lens, and some provide as much as a 6X or 10X zoom. Don't put too much stock in digital zoom, which is a software feature that has nothing to do with the lens. It merely enlarges a small portion of the image at the expense of picture detail. If you'll be doing a lot of low-light shooting, look for a fast lens--that is, a lens with a maximum aperture setting of f-1.8 or f-2.8. The lower the f-stop, the faster the lens and the more you'll be able to capture in low light. Most consumer digital-camera lenses are permanently attached to the camera body, but many are compatible with wide-angle, close-up, telephoto, or even fish-eye attachments. If you want to use a lens shade or a filter, make sure that the camera lens is threaded so that you can attach it. Some advanced digital cameras are compatible with 35mm film-camera lens systems, letting you choose the lens that's most appropriate for your subject.

Sensor
Once light passes through the lens of a digital camera, it's captured by a CCD or a CMOS sensor. The sensor is covered with photosensitive pixels (short for picture elements); the more pixels on the sensor, the higher the sensor resolution. And, of course, the higher the sensor resolution, the higher the resolution of the images captured by that sensor. Higher-resolution images are sharper and show more detail, but they also require more storage space and can quickly fill a camera's media. Casual snapshots look fine at 640x480 pixels when displayed onscreen. But if you want to print your photos or crop them to highlight particular areas, you'll need more than 1 megapixel to get adequate image quality. The resolution you need in an image increases with the size at which you want to print it. If you want to enlarge your photos to sizes greater than 5x7 inches, you probably won't be satisfied with the results from a sub-2-megapixel camera.

Media
Unless you're purchasing an inexpensive digicam that has internal memory only, you should expect to find some type of removable image storage medium when you open the box. When you press the shutter-release button to take a shot with your digital camera, the image that the sensor captures is saved on the storage medium. There are many types of media for digital cameras, but most models are compatible with only one. The most common are CompactFlash and SmartMedia. Many Sony cameras use Memory Stick and some use mini-CDs or floppy disks. MultiMedia Cards (MMC), IBM Microdrives, and some proprietary media types are also used. Make sure you get a camera that is compatible with the type of media that offers enough storage space to meet your needs. Most types of media are available with a range of capacities--and prices--and you'll probably want to purchase extra media with a greater capacity than what's included with your camera. Check out our feature on media options to get a handle on which type is best for you.

Viewfinder and LCD
Most digital cameras have an optical viewfinder that works just like the ones on film cameras: hold it up to your eye, frame the scene you want, and shoot. If you wear glasses, look for an optical viewfinder with a diopter so that you can adjust the viewfinder focus. If you're buying a camera that costs more than a couple hundred dollars, you should expect it to have an LCD screen too. This usually serves as a viewfinder, an image-playback screen, and a display that gives you access to camera features and functions through a menu system. Look for a sharp LCD that shows a clear image in both bright and dim light. Some cameras let you adjust the brightness and backlighting of the LCD, which is helpful. An LCD is usually located on the back of the camera, and some can be folded out and swiveled, much like the ones on video cameras. Another similarity to video cameras can be found in digicams that use electronic viewfinders (EVFs) instead of optical ones. You hold the camera up to your eye and look through an eyepiece to use an EVF, but the image you see is just like the LCD image. If you buy this kind of camera, give the EVF a look first to make sure that the display isn't jumpy when you zoom and pan.

Batteries
Every digital camera should ship with alkaline, lithium-ion, or nickel-metal-hydride batteries. Alkaline batteries are convenient because you can buy them anywhere, but they don't have as long a life as other power sources. Cameras that use longer-lasting, rechargeable lithium-ion or nickel-metal-hydride batteries should also come with a charging module. Some cameras can use more than one battery type, which gives you both the convenience of alkalines and the longer life of rechargeables. Most cameras also come with an AC adapter so that you can save some battery life while shooting indoors or downloading photos to your computer. If an adapter isn't included with the model you want, it's a good idea to buy one separately. Whatever battery you end up with, be sure to have enough spares when you take your camera on the road.

Flash
Shooting under low-light conditions can be tricky, so you'll need a reliable built-in automatic flash. Look for a camera that offers red-eye-reduction flash for shooting people and animals. Other helpful features are forced (fill) flash, slow-sync flash, and adjustable illumination levels. Twilight-scene modes generally use a slow-sync flash to illuminate a subject in the foreground of a dimly lit scene while capturing adequate detail in the background. If you need more power and flexibility from your flash than the built-in unit gives you, you may want to purchase an external flash unit. Only cameras equipped with a hotshoe or contact are compatible with off-camera flashes. Some manufacturers offer dedicated units that are designed to work with particular camera models, but if there's no recommended flash unit for your digicam, you can find a wide range of flash units available from better photo-equipment retailers.

Popular camera features

Exposure modes
Every digital camera has a fully automatic mode that lets you simply point and shoot. Program auto-exposure modes keep the basic exposure settings automatic while giving you manual access to other camera settings. If you want more control over exposure, look for a model that offers aperture- and shutter-priority modes, which let you set the f-stop or shutter speed, then automatically calculate the other settings needed to expose your image correctly. For total control, look for a full manual exposure mode.

Many digital cameras offer exposure compensation. This feature allows you to make adjustments to the automatic exposure setting in situations where the camera's light meter might have trouble. For example, if you're shooting a person against a bright background, the person might come out looking very dark in the picture. That's because most of the area that the camera's metering system read to calculate the exposure was much brighter than the person. By using exposure compensation, you can correct the settings so that your subject gets enough light. Some advanced cameras offer automatic exposure bracketing. This feature shoots several frames when you release the shutter, each at a different exposure setting. You can then choose the one with the exposure you like best.

Macro mode
If you like taking close-up shots or photographing small subjects, such as wildflowers or insects, you'll need a camera with a macro mode. Look for one with a minimum focus distance of less than five inches if you really like to get in close.

Continuous-shooting or burst mode
Attaining fast enough shooting speed has been one of the biggest hurdles for digital camera makers. Early digicam users can attest to the frustration of waiting around for their cameras to save one shot to the memory before they could shoot the next one. Recently, shot-to-shot times have gotten faster, and shutter lags--the pauses between the time when you hit the shutter-release button and the moment the shot is captured--have decreased. But capturing fast action can still be tricky with a digital camera. One way manufacturers have dealt with the problem is by offering burst or continuous-shooting modes. Like a motor drive on a film camera, continuous-shooting mode lets you capture several photos in very quick succession. When it's done shooting, the camera usually takes a long pause to save all those images to the memory, but continuous shooting is still a useful tool for photographing subjects in motion.

Scene modes
Many digital cameras offer special modes that optimize the camera settings for specific types of scenes. Landscape, portrait, twilight, and pan-focus are among the most common scene modes. Scene modes can affect both exposure and focus settings, and a panorama mode lets you shoot a scene in several frames, then "stitch" them together to make one big picture. Look for a camera that offers scene modes that correspond to your favorite photo subjects. If you think you'll use this feature a lot, make sure that the camera you buy gives you easy access to it through a button or dial, instead of making you hunt through the LCD menu to find it.

White balance
All digital cameras offer an automatic white-balance setting that allows the camera to calculate the right color balance for your shot. Many models also let you select among white-balance presets that are calibrated for particular types of lighting, such as sunny, cloudy, incandescent, or fluorescent. If you're going to be doing a lot of shooting under fluorescent light, look for a camera with presets for all three types--or at least make sure that the fluorescent setting on the camera you choose matches the type of fluorescent light you'll be using. Manual or custom white-balance controls let you take a reading from an area that you want to appear as pure white in your picture, then use that reading to calculate the color balance. Some advanced cameras also offer white-balance bracketing or let you adjust the red, green, and blue color channels separately. If you're using studio lighting, you might want a semipro camera that provides white-balance presets labeled by color temperature instead of lighting type.

Video and audio modes
If you're serious about shooting videos, stop reading right here and go look for a dedicated video camera. The resolution and features available for video capture on digital still cameras just can't compete with what you get from a camcorder. That said, if you're not planning on sending your next clip to Sundance and just want to have some fun, there are lots of digital cameras that are ready to accommodate you. Some cameras record silent video only or save only short clips. If you want to get the most motion-picture power out of a still camera, look for one that captures sound with the video and offers an extended video mode. Extended modes let you shoot as much video as your media will hold. Some cameras offer audio modes that let you annotate still shots with brief recordings or use the camera as a voice recorder.