Digital cameras glossary
16:9 widescreen photo mode
Many digital cameras offer this mode to let you take photos that have the same shape as a 16:9 aspect ratio widescreen TV. This size is ideal if you plan on showing your pictures on your high-def set, because they'll fill up the TV's entire screen without losing any picture information.
See focal length.
Some cameras come with audio/video cables to let you send an image or video with sound to a TV for easier viewing. Older models may have dedicated A/V outputs, while newer models might include a cable with RCA plugs on one end and a proprietary connector on the other. Many cameras offer HDMI connectivity for displaying high-resolution images and videos on a compatible TV.
A small metal fitting on the top of a camera that lets you add optional accessories, like an external flash, wireless transmitter, or external microphone. Accessory shoes that can also supply power are also known as hot shoes.
A technology found in some digital cameras that alerts you if your subject blinks when you take a photo. Some anti-blink modes will also capture two shots in a sequence and save the one where the subject's eyes are open.
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 as well as an aperture priority mode, which allows you to choose the f-stop while the camera adjusts all of the other settings for optimal exposure.
Aspherical lens element
A camera lens is made up of different lens elements, most of which have a spherical profile. The more spherical elements are used in its construction, the bulkier a lens will be. Aspherical lens elements are used to create smaller, lighter lenses with clear focus across the entire field of the lens from one edge to the other.
Automatic scene selector
A feature that identifies the kind of shot you're trying to take — such as a landscape, sports photo, or portrait — and adjusts the camera's exposure, shutter speed, white balance, and other settings to take the best picture possible.
Digital cameras use a buffer to temporarily store photos before committing them to a regular memory card. That way you don't have to wait for each image to be stored before taking your next shot, and can shoot more quickly or even use a rapidfire "continuous" or "burst" mode.
See continuous/burst mode.
Also known as CA, or fringing. Most of the time, a camera lens is able to direct all light waves onto the same focal plane. Sometimes, however, it magnifies a few wavelengths differently, or can't quite get them focused on the same plane. The result is a mild mismatch within the image, so that it appears blurred or objects appear to have colored edges. This effect can be pronounced in high-contrast situations and when using larger apertures. Lens manufacturers use special optical designs and lens elements to minimize chromatic aberrations, and many DSLR cameras have special processing to minimize the effect. Chromatic aberrations can also be reduced in post-processing.
CMOS (complementary metal oxide semiconductor)
See image sensor.
CompactFlash cards are used in some digital cameras (especially digital SLRs) and other small portable digital devices. They are available in a range of capacities up to 64GB, or even more. UDMA (Ultra Direct Memory Access) CompactFlash cards offer higher data transfer speeds than standard CF cards when used with UDMA-enabled digital SLR cameras and card readers and the UDMA modes are rated by number from 0-7, with higher numbers meaning faster transfer speeds . This is great for folks who use their camera's movie mode, or need to shoot a lot of photos in quick succession and download them rapidly to their computer.
Continuous autofocus mode
In this mode, a camera continually focuses on the subject or subjects in your field of view. It's ideal for recording action scenes, high-energy kids, or other subjects when you want to snap multiple photos in quick succession.
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 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 determines the focal length your lens appears to be when it's mounted to a digital SLR camera.
So why would the equivalent focal length be different from the focal length printed on the lens barrel? Because the lens's focal length is based on the traditional 35mm film format. Since the image sensor on many DSLRs is smaller than a full frame of 35mm film, the result is a seemingly more telephoto focal length than that printed on the barrel.
To find the effective focal length of a lens mounted to an SLR, you multiply its actual focal length by your camera'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 SLRs have a crop factor of 1.5 or 1.6, but different camera brands and models have slightly different-sized sensors, and that will affect each camera's exact crop factor. Full-frame digital SLRs use image sensors that are the same size as a frame of 35mm film, and therefore have no 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.|
Cross-type focus sensor
A type of focusing sensor found in DSLRs that detects and focuses on a subject along both vertical and horizontal lines. They provide higher-accuracy focusing than more commonly found vertical line sensors. High-end DSLRs tend to have cross-type sensors more often than entry level or midrange models.
Depth of field
Depth of field (sometimes abbreviated as DOF) describes the areas to the fore and rear of the main focus point that remain sharp, or in focus. With an extremely shallow depth of field, even areas just in front of or behind that point will be out of focus. With a wide depth of field, much of the photograph may be crisply in focus. That's not to say that wider depth of field is always desirable; for instance, many portrait photographers rely on a fairly shallow depth of field to achieve crisp portraits with a blurred background and foreground. Depth of field is affected by factors such as aperture and focal length, although subject distance and sensor type can come into play as well.
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.)
An indicator of your image sensor's ability to capture highlight detail and shadow detail at the same time (or, sometimes, a way to discuss an individual photograph's ability to show detailed dark areas and detailed bright areas at the same time). Because your sensor's pixels can only collect so much light, it is possible to lose detail at one or the other end of the spectrum, particularly when you're shooting a high-contrast scene. The sensors associated with DSLRs frequently boast a better dynamic range for the simple fact that each pixel is physically larger and thus able to collect more light information. Good dynamic range generally gives you photographs with more dimensionality and pop.
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 pixel resolution.
EXIF (Exchangeable Image File Format)
Information like focal length, aperture, shutter speed and ISO, along with many other camera settings, is recorded automatically into photographs taken with any digital camera. EXIF data can be extracted from JPEG files, and is a valuable tool for photographers who are learning and want to understand how different settings lead to different results.
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 cameras have greater and lesser levels of control over exposure settings.
A feature that lets you adjust the camera's light metering to allow for shooting conditions. A camera's built-in light meter offers a recommended exposure to help photographers set aperture and shutter speed correctly. However, sometimes your camera's best guess isn't quite right (like when your subjects are in front of a bright picture window, and the camera exposes the surrounding scene correctly but leaves your subjects too dark). With exposure compensation, you can tell the camera to increase or decrease exposure values by increments of either 1/3 or 1/2 steps. Then, you can either adjust the exposure yourself, based on that light meter reading, or, if you're in automatic, shutter priority, or aperture priority mode, let the camera set the exposure for you.
Face detection is a technology commonly found in point-and-shoot cameras, as well as most mirrorless cameras and DSLRs. 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.
Flash exposure compensation
A feature found on digital cameras that lets you adjust the light output of the flash to increase or decrease its intensity. This allows you to lighten or darken a scene to your own preferences, beyond what your camera automatically selects.
Focal length is a measure of the distance (in millimeters) from the optical center of the camera's lens to the image sensor. A digital camera’s focal length is measured differently from that of a 35mm film camera (see crop factor), so manufacturers usually give a "35mm equivalent" focal length in their specs to provide an accurate idea of the camera’s wide-angle or telephoto capabilities. Most digital cameras have a zoom lens, which can change focal lengths. A fixed lens has only one focal length.
Focus (auto & manual)
Nearly every digital camera utilizes some kind of autofocus capability, a technology which lets the camera automatically create sharp images of the central subject in the frame as you press the shutter button. Most 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.
Full frame image sensor
Some advanced digital SLR cameras feature an image sensor that has the same dimensions as a frame of 35mm film found on traditional film SLRs, which is much larger in physical size than sensors found in most digital cameras. All that extra surface area on these "full frame" sensors has several benefits: superior light gathering, lower noise levels, and better resolution. You can make extra-large prints of photos shot on a full-frame DSLR and still maintain high image quality. You can also crop these photos significantly without losing detail.
A simple graph that offers an objective view of exposure by displaying brightness and darkness values for a photograph. When you know how to read it, a histogram can tell you whether you need to use exposure compensation on your next shot with greater accuracy than the preview of the last shot on your LCD screen.
See accessory shoe.
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.
Two technologies used to capture digital images 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.
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.
An image coding system that processes picture information captured by a camera's image sensor and compresses it for storage on a memory card. Most cameras offer a selection of JPEG settings to let you adjust the amount of compression in your photos— basic JPEG settings with greater compression levels let you store more pictures on any given memory card, but with reduced image quality. Fine or high quality JPEG settings with less compression give you more detailed photos, but you won't be able to store as many of them on your memory card. If you think you will be enlarging or printing your results, it's better to use a higher quality JPEG setting, but if you're just planning on uploading your photos to a social media site, basic or normal JPEG settings will work fine.
Color LCD viewscreens can operate in place of, or in addition to, traditional viewfinders. Most cameras' LCDs measure between 1.8" and 3.5" diagonally, with resolutions of up to a million or more pixels. The higher the LCD's resolution, the clearer your view will be of images and camera menus.
Lag time refers to the pause between when you push the shutter button and when the camera actually takes a picture. With point-and-shoot cameras, this usually happens because the camera needs to set focus and adjust settings before taking the picture. One workaround is to half-depress the shutter button to autofocus the camera on your subject in advance; then you just press down the rest of the way when you're ready to take the picture.
Digital SLRs have little to no shutter lag outside of full auto mode or Live View mode, where they perform more like point-and-shoot cameras. As a result of their mirrorless design, mirrorless cameras have little lag time in Live View mode. The increased responsiveness of these two camera types is one of their main selling points over point-and-shoot models.
Most camera lenses are actually an assembly of multiple glass lenses, or elements, arranged in groups. Each element directs light toward the image sensor in a different way so that the final image is crisp, well-exposed, and free of distortion. The front and rear lens elements are exposed to the elements, so it is important to use a cap on each end of the lens when not in use. These front and rear elements typically have a coating to minimize lens flare and aberrations.
A macro, or close-up, lens is one that lets you focus on subjects that are very close to the lens. A macro lens is perfect for shooting close-ups of flowers, insects, or other small objects. Macro lenses come in a range of focal lengths — anything from 28mm to 200mm and beyond.
Many point-and-shoot cameras also offer a "Macro" mode. This mode changes the focus setting to let the camera focus on subjects that are very close to the lens. If a macro mode is important to you, 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 detailed your close-ups will be.
One million pixels. The more megapixels a camera has, the higher its maximum resolution — and the better its potential picture quality.
Digital cameras store the photos they take to some kind of memory card. A few cameras 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.
Just like DSLRs, mirrorless cameras, also known as "micro four thirds", or "compact system" cameras, feature large image sensors for beautiful pictures, and they let you swap lenses for different shooting scenarios. Their mirrorless designs allow the camera body and lenses to be smaller and more portable than DSLR bodies and lenses.
Most cameras let you record video in HD resolution with audio. While the movie modes on point-and-shoot cameras cannot replace the high-quality video and versatility you get from a camcorder, they can be another fun way to capture faces or events.
Today’s DSLR cameras feature advanced movie modes. Accessories like external microphones and lenses with near-silent autofocus give you audio quality that matches the high-quality video these cameras are capable of producing. Entire movies, commercials, and TV shows have been filmed with DSLRs.
When shooting darker scenes with a higher ISO setting, you’ll find that your photos appear grainy. Noise reduction is the application of one or more algorithms to a photo in order to eliminate graininess in a photo. With effective noise reduction, you can eliminate much of the noise without losing sharpness. Most cameras have some degree of built-in noise reduction.
Some also offer a long-exposure noise reduction mode, as long-exposure shots can accentuate the problem of noise. Photography enthusiasts may choose to disable their camera's noise reduction in order to use more sophisticated, user-adjustable noise reduction software when processing their images.
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 20X, 3X being less range and 20X 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. With interchangeable DSLR and mirrorless camera lenses, optical zoom refers to the level of magnification from the shortest focal length to the longest.
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.
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 detects. The more pixels an image sensor has, the higher the camera's potential resolution.
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, and vice versa.
RAW image format
A mode found on DSLRs, most mirrorless cameras, 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.
A shooting mode found on DSLRs, most hybrids, and a few point-and-shoot models that allows the camera to capture and store unprocessed, lossless RAW images plus much smaller, compressed JPEG files at the same time. The unprocessed RAW image files can provide greater picture detail for advanced editing with specialized software on a computer. The JPEG files are ready to view or print right from the camera with no further processing required.
The number of pixels used to capture an image. Resolution ranges from low (640 x 480) to high (3456 x 2592 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. If you intend to make large prints of your photos, it's best to go with the highest resolution possible, while a lower resolution will work fine for sharing your photos online.
Most cameras offer what are called "scene modes" — settings that are optimized for the demands of certain kinds of photographic scenes or subjects. Some common examples include an action/sports mode that increases a camera's sensitivity, so it can capture crisp shots of intense action without blurring the subject; or a night scene mode that slows down the camera's shutter speed to capture a darkened scene more accurately, with little or no help from the flash.
A Secure Digital® (SD) card is a flash memory card used in many digital cameras, memory players, and other portable digital devices. You'll also come across SDHC and SDXC cards — they're higher-capacity SD card formats. Be sure to check your owner's manual to confirm compatibility before buying an SDHC or SDXC card.
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.
Digital camera manufacturers have had to create ISO settings to approximate film sensitivity. Most digital cameras use 100 as their standard ISO setting, and offer a range of other settings to mimic the effects of using film with varying speeds. Higher ISO settings can be useful in low-light shooting conditions or when faster shutter speeds are required, but they can result in an increase of visible noise, giving your pictures a somewhat grainy look.
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 work best with a tripod, since the human hand cannot hold a camera steady for very long). Simple cameras may have very little shutter speed adjustment, while more sophisticated models 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 an electronic sensor record the image. SLRs are revered by photo enthusiasts 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.
A telephoto lens makes it possible to capture crisp, close-up shots of faraway subjects. The longer the camera's 35mm equivalent focal length, the more telephoto shooting ability the camera has. For example, a 28-300mm equivalent lens has more telephoto power than a wide-angle lens with a 10-24mm equivalent focal length. Often digital camera users refer to optical zoom measurements to indicate a camera's telephoto ability.
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.
Using a viewfinder is the traditional method of framing photos prior to shooting. Most point-and-shoot 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 stability because you're holding your arms in closer with the camera up to your eye. Many cameras offer an optical viewfinder, just like the ones found on film cameras. A few cameras have electronic viewfinders (EVF) that use a color LCD to show what the lens sees.
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 helps with accurate color retention. All digital cameras offer automatic white balance settings, and most feature additional preset levels or even custom manual settings. These settings can provide better color accuracy than the automatic settings when shooting with different light sources like incandescent, fluorescent, and daylight.
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 10-24mm equivalent lens has more wide-angle capability than a telephoto-oriented 28-300mm equivalent lens.