35mm equivalent
See focal length.

A/V outputs
Video or audio/video outputs are found on most digital cameras; they let you send an image to a TV for easier viewing. An A/V output will also let you send sound (if your camera has that capability, and you recorded a sound clip), while a video output only sends images.

Aperture
A camera's aperture works like the iris of your eye, expanding and contracting to adjust the amount of light which passes through the lens. Aperture is measured in "f-stops." A higher f-stop number corresponds to a smaller opening, which admits less light. Aperture settings are directly related to exposure, permitting you to control the amount of light that reaches your camera's image sensor. Some cameras offer manual aperture adjustment; others offer an aperture priority mode for changing exposure settings.

Burst mode
See continuous/burst mode.

CCD (charge coupled device)
See image sensor.

CMOS (complementary metal oxide semiconductor)
See image sensor.

CompactFlash® card
A popular form of removable media originally developed by SanDisk. CompactFlash cards are used in some digital cameras (especially digital SLRs), PDAs and handhelds, and other small portable digital devices. They are available in a range of capacities, from 256MB to as much as 8GB, or more.

Continuous/burst mode
Continuous mode, often called burst mode, lets you press and hold a camera's shutter button to capture a series of shots in rapid succession. This mode is great for recording action scenes, high-energy kids, and pets. Even if one shot of your daughter scoring the winning goal turns out blurry, you've still got plenty more to choose from. Depending on the camera, you may be able to take three, ten, or even more shots in one continuous burst, then select and keep just the images you like best.

Crop factor (focal length multiplier)
If you own a digital SLR camera, you may have heard of crop factor, or focal length multiplier. Basically, crop factor affects how telephoto or wide angle your lenses appear to be when they're mounted to a digital SLR camera, as opposed to a traditional 35mm film camera. That's because the image sensor on most DSLRs is smaller than a full frame of 35mm film, and when you look through the viewfinder of a DSLR camera you see what your image sensor sees. To find the effective focal length of a lens mounted to your SLR, you multiply its actual focal length by your cam's crop factor. For example, a 70-300mm lens, x 1.5 crop factor, will seem like a 105-450mm lens on your DSLR. Most digital SLR's have a crop factor of 1.5 or 1.6, but different camera brands and models have different-sized sensors, and that will affect each camera's exact crop factor.

A frame of 35mm film captures the entire image area produced by a lens mounted to a film SLR camera.	A digital SLR's sensor records only the center portion of the image from the same lens, effectively cropping it.
The resulting image appears closer when seen through the viewfinder, providing more apparent telephoto power.

Digital zoom
The ability to magnify an optical image digitally, using interpolation. Digital cameras can come with quite high levels of digital zoom, but the image quality suffers noticeably as more digital zoom is applied. (Generally, you'll want to stick to optical zoom to ensure a crisp, detailed photo.)

Effective pixel count
There are two different ways to think about the pixels on a camera's image sensor. "Actual" pixels is a simple count of every pixel present on the sensor. "Effective" pixels, however, is a count of all the pixels used to record an image and it's almost always a tiny bit lower than the "actual" count, because some pixels on a sensor aren't used to record picture information. Effective pixel count is widely used, because it's a much more accurate way to assess a camera's maximum picture capture capability.

Exif Print
An Exif Print-capable camera is great if you're going to be printing out photos on an Exif Print-compatible photo printer. The camera records information like exposure settings and light metering at the time when a photo was taken, and attaches that information to the picture file. A compatible printer takes note of this info and adjusts its settings accordingly, to permit the most accurate, lifelike photo print possible.

Exposure
Exposure refers to the amount of light to which the camera's image sensor is exposed. Three factors go into exposure: aperture, shutter speed, and sensitivity. By adjusting these factors, either separately and manually, or by using predefined exposure settings, you can affect the way your digital camera handles photos taken in unusual settings (such as pictures taken of people running, or at twilight). Different digital cameras have greater and lesser levels of control over exposure settings.

Face detection
Face detection is a recent technology commonly found in point-and-shoot cameras. It recognizes one or more human faces in your frame, and sets focus priority on the people in your shot. Let's say you want a picture of your child peeking between two fence posts. Instead of focusing on the more obvious posts, face detection tells the camera to zero in on the child instead, giving you a clear, precisely focused portrait. Face detection can also trigger the camera to select optimal exposure, white balance, and flash settings to best suit your subject.

Film speed
See sensitivity.

Focal length
Focal length is a measure of the distance (in millimeters) from the optical center of a camera's lens to its focal point, which is located on the image sensor. Because digital cameras' focal lengths are measured differently than traditional film cameras, manufacturers usually give a "35mm equivalent" focal length in their specs. This helps 35mm film photographers get a better idea of just how wide-angle or telephoto a digital camera will be in relation to their film cam. A typical digital camera's 35mm equivalent focal length might be 28-280mm, while its actual focal length measures 4.6-46mm. The reason that a range of numbers is given here (28mm to 280mm) is due to the fact that most digital cameras have a zoom lens, which can change focal lengths. A fixed lens has only one focal length.

A camera lens's focal length can tell you a lot about what kinds of pictures it will be able to take well. With a long focal length, like 280mm, a camera is better able to capture far-off subjects (such a lens is also known as "telephoto"). With a short focal length, like 28mm, a camera can capture the scene immediately before it more completely (this kind of lens is considered "wide-angle").

Focus (auto & manual)
Nearly every digital camera utilizes some kind of autofocus capability, a technology which lets the camera focus automatically on the central subject in the frame as you press the shutter button. Many offer multipoint autofocus, which makes it easier to take tricky shots like off-center portraits. Multipoint autofocus uses several points (often between 3 and 9) to assess a framed shot and set focus. Selectable multipoint autofocus gives the user control over which point is used as the focus point.

More sophisticated cameras may also offer manual focus, either as a set of predetermined focus settings, or as a manual focus ring or lever. Manual focus gives you increased control over the detail and clarity of your photos, especially if you plan on taking non-traditional shots and close-ups.

F-stop
See aperture.

Image sensor
A digital camera's image sensing element, or as it's often referred to, its image sensor. The image sensor's job is to convert light to electrical energy, which can then be stored in digital form in the camera's memory. An image sensor's photo-capturing power is measured in pixels, and will usually be seen expressed in megapixels. Sometimes, you may see two slightly different pixel counts listed for the same camera's sensor. These numbers represent effective pixel count and actual pixel count.

The two most commonly found technologies used to capture digital images in today's cameras are CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor) image sensors. Although both types have their unique strengths and weaknesses, neither one is inherently superior to the other. You can expect high-quality digital photographs from cameras using either technology.

Image stabilization
A feature that reduces the blurring of images that occurs as a result of camera shake when taking hand-held shots, particularly at slow shutter speeds or when using telephoto lenses. Optical image stabilization works by using built-in vibration sensors to steer a special set of optical elements inside the lens that compensate for camera movement. Sensor-shifting stabilization works in much the same way, but instead of moving lens elements, the vibration sensors counteract camera shake by moving the image sensor itself.

ISO film speed equivalency
See sensitivity.

LCD viewscreen
Color LCD viewscreens are pretty much the norm on today's digital cameras; they can operate in place of, or in addition to, traditional viewfinders. Most cameras' LCDs measure between 1.8" and 3.5" diagonally, with resolutions between 100,000 and 240,000 pixels. The higher the LCD's resolution, the clearer your view will be of images and camera menus.

Live view mode
In traditional digital SLR cameras, the LCD viewscreen can only be used to play back captured images; you still need to look through the viewfinder to compose your pictures. However, some newer models now offer a live view mode that allows use of the LCD to both compose and review photos, just as you would with a point-and-shoot camera.

Macro mode
Many digital cameras offer a "Macro" mode. This mode changes the focus setting to let the camera focus on subjects that are very close to the lens. Macro mode is perfect for shooting close-ups of flowers or insects. When shopping, be sure to check how close the Macro mode lets you get — can you shoot objects as close as an inch, or only as close as five inches? The closer you can get, the more impressive such close-ups are.

Megapixel
One million pixels. The more megapixels a camera has, the higher its maximum resolution — and the better its potential picture quality.

Memory
Digital cameras store the photos they take to some kind of memory. In nearly all cases, this will be some kind of removable media. Many cams also include a small amount of built-in memory — enough to let you capture a few extra shots if your memory card fills up, but not enough for regular everyday shooting.

Memory Stick®
Originally developed by Sony, Memory Stick is a form of removable media used in digital cameras, digital camcorders, handhelds, printers, and more.

Movie mode
Most digital cameras, with the exception of digital SLRs, let you record video either as an MPEG movie or a Motion JPEG movie. Most record audio too. Although these movie modes cannot replace the high-quality video and versatility you get from a digital camcorder, they can be another fun way to capture faces or events.

Optical zoom
The ability to magnify a subject for close-ups, by adjusting the camera's lens assembly (thus the name "optical"). Most current digital cameras include an optical zoom lens of some kind. The amount of zoom commonly varies between 3X and 18X, 3X being less range and 18X being considerably more. Although optical zoom specifications may look low compared to digital zoom specifications, remember that optical zoom is the way to go, since it won't result in image degradation.

PictBridge
PictBridge is an international direct-print standard adopted by most major manufacturers of digital cameras and photo printers. With PictBridge, you can connect a compatible camera to a PictBridge photo printer via a USB cable, for easy direct printing without the use of a computer. The gear doesn't have to be the same brand — it just has to be PictBridge-capable.

Pixel
Short for "picture element." A digital camera's image sensor consists of millions of pixels, each one building up a tiny charge of electricity in response to the light it "sees." The more pixels an image sensor has, the higher the camera's potential resolution. Also see effective pixel count for more info.

Priority modes
Aperture and shutter speed priority modes are a shortcut to easy exposure adjustment. To set exposure manually, you would need to adjust aperture and shutter speed settings separately. With priority modes, when you adjust aperture, shutter speed is automatically reset appropriately — or vice versa. It's a nice way to get more creative without having to worry about understanding all the details behind these kinds of adjustments.

RAW image format
A mode found on digital SLRs (and a few point-and-shoot models) that allows all the digital data captured by a camera's image sensor to be stored without first being processed or adjusted by the camera's image processor. The resulting RAW image files, or "digital negatives," can provide greater picture detail, allowing for advanced editing with specialized software on a computer. You won't need to use RAW files if you usually print photos directly from your camera's memory card, but folks who like to customize their images tend to appreciate the extra flexibility and picture quality that RAW files offer.

Removable media
All of our digital cameras use some kind of reusable removable memory, such as Memory Sticks, CompactFlash cards, and Secure Digital cards. These memory cards offer varying amounts of storage — the more megabytes, or MB, of memory, the more images that can be stored. See our Blank Media Glossary for more info.

Resolution
The number of pixels used to capture an image. Resolution ranges from low (640 x 480) to high (2592 x 1944 and up). High resolution makes for sharper pictures; however, high-resolution photos take up more memory than lower-res photos. Different levels of resolution are appropriate for different purposes; see this chart for a few suggestions.

Secure Digital® (SD) card
A Secure Digital (SD) card is an SDMI-compliant flash memory card used in many digital cameras, memory players, and other portable digital devices. Like other SDMI-compliant cards, an SD card uses an extra chip to recognize and comply with the requirements imposed on copyright-protected materials.

You'll also come across SDHC cards, a newer, high-capacity SD card format. Now, while any SDHC-compliant camera or PDA will be compatible with standard SD cards, an SD-compatible device will not necessarily work with SDHC cards. In fact, if your device is more than a year or two old, chances are it won't be SDHC-compliant. And there are quite a few newer devices that won't work with SDHC cards either. So be sure to check your owner's manual to confirm compatibility before buying an SDHC card.

Sensitivity
With traditional film cameras, sensitivity, also known as ISO, represents the film's sensitivity to light. A lower ISO number means that the film needs more light to take a picture than film with a higher ISO.

Because digital cameras do not use film, manufacturers have had to create "sensitivity" settings. Most digital cameras use 100 as their standard ISO sensitivity setting, and offer a range of other settings from 200 to 400, or more, to mimic the effects of using film with speeds of 100, 200, 400, etc. These higher settings can be very useful in low-light shooting conditions; however, because they are achieved by amplifying or boosting the image sensor's output, they can result in an increase of visible "noise," giving your pictures a somewhat "grainy" look.

Shutter speed
The speed at which a digital camera's shutter exposes the image sensor to light. A shutter speed of 1/60 means that the sensor is exposed to light for 1/60th of a second. Faster shutter speeds are good for "freezing" fast-moving action; slow ones allow you to intentionally blur the movement of your subject to emphasize motion, such as water traveling over a set of falls (these types of shots may require a tripod, since the human hand cannot hold a camera steady for very long). Simple digital cameras may have very little shutter speed adjustment; more sophisticated cams often have between 9 and 15 shutter speeds. Many cameras also offer shutter speed priority mode.

Single-lens reflex (SLR)
An SLR, or single-lens reflex, camera is named for its picture-taking mechanism. In a film SLR, the viewfinder uses a 45°-angled mirror to see through the lens; that mirror snaps out of sight quickly when you press the shutter button, to let light enter and expose the film. A digital SLR works the same way, except that the shutter is opening to let the CCD record the image. SLRs are revered by serious photographers because they permit the use of many different specialized lenses and flashes, and provide faster response time and higher continuous shooting speed than most point-and-shoot cameras.

Telephoto lens
A telephoto lens makes it possible to capture crisp, close-up shots of far-away subjects. The longer the camera's 35mm equivalent focal length, the more telephoto shooting ability the camera has. For example, a 38-300mm equivalent lens has more telephoto power than a wide-angle lens with a 28-140mm equivalent focal length. Often digital camera users refer to optical zoom measurements to indicate a camera's telephoto ability.

USB
USB (Universal Serial Bus) is a "plug and play" interface commonly used on digital cameras, because it allows for quick, easy transfer of digital photos between a camera and a computer or printer. For more information, check out our discussion of USB in the Connections Glossary.

Viewfinder
A viewfinder is the small square on the back of a camera that the photographer holds up to his eye. Using the viewfinder is the traditional method of framing photos prior to shooting. Many digital cameras offer an optical viewfinder, just like the ones found on film cameras. A few cameras, most notably those with high-powered telephoto zoom lenses, have electronic viewfinders (EVF) that use a color LCD to show what the lens is seeing, much like a camcorder's viewfinder. A growing number of cameras have given up the viewfinder altogether; framing photos requires you to use the LCD viewscreen. Although a viewfinder doesn't provide as big an image as a viewscreen, it may be preferable when shooting outdoors in direct sunlight, which can wash out the image on a viewscreen. Using a viewfinder can also provide greater freedom from camera shake because the camera is being held against your face for stability while snapping photos.

White balance
White balance is the electronic adjustment of light levels to remove unrealistic color tones or hues, so that objects that appear white in person are rendered white in your photos. This process helps recorded images to retain their true colors. All digital cameras offer automatic white balance, and most feature additional preset levels or even custom manual settings. These manual adjustments can provide better color accuracy than the automatic settings when shooting under a mixture of light sources such as incandescent, fluorescent, and daylight.

Wide-angle lens
A wide-angle lens can capture an extra-wide view of the scene immediately before a camera. This allows you to more easily photograph panoramic landscapes for example, or take big group shots without forcing everyone to squeeze together. The shorter (or lower) a lens's 35mm equivalent focal length, the more wide-angle shooting ability the camera has. For example, a 28-140mm equivalent lens has more wide-angle capture ability than a telephoto-oriented 38-300mm equivalent lens.