Megabyte
A megabyte (MB) is a unit of data used to describe the size of digital images and the capacity of a digital memory card. Memory cards are available in sizes ranging from 8MB to 2 Gigabytes (a Gigabyte is the equivalent of 1,024MB).

Megapixel
A measure of resolution that reflects the ability of a digital camera to record detail. The more megapixels a camera has, the more detail its images can contain and the more they can be enlarged without losing clarity. More megapixels aren't always necessary, however. For more information see DCHQ's

Movie mode
Many digital cameras let you record short clips of highly compressed, low-resolution video, either as an MPEG movie or a Motion JPEG movie. (320 x 240 is a common resolution.) Some record audio too. Although these low-resolution movie modes cannot replace the high-quality video you get from a digital camcorder, they can be another fun way to capture faces or events.

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Optical zoom
The ability to magnify a subject for close-ups, or pull back for wide shots. Most current digital cameras include a variable optical zoom lens. Specs for zoom commonly vary between 2X and 10X, 2X being less range and 10X being considerably more. Although optical zoom specifications may look low compared to digital zoom specifications, remember that optical zoom does not result in image degradation.

Pixel
Short for "picture element." A digital camera's CCD consists of millions of pixels, each one building up a tiny charge of electricity in response to the light it "sees." The more pixels a CCD has, the higher the camera's potential resolution. Visit our FAQ for more info on effective pixel count and actual pixel count.

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Priority modes
Aperture and shutter speed priority modes are a shortcut to easy exposure adjustment. To set exposure manually, you would need to separately adjust aperture and shutter speed settings. 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.

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Removable media
All of our digital cameras use some kind of removable memory, such as Memory Sticks, CompactFlash cards, Secure Digital cards, floppy disks, and mini CD-Rs or -RWs. With the exception of mini CD-Rs, this memory is reusable. It varies in how much storage it offers (the more megabytes, or MB, of memory, the more images can be stored) and in how much it costs to buy extra storage. See our Blank Media discussion for more info.

Resolution
The number of pixels used to capture an image. Resolution ranges from low (320 x 240) to high (2048 x 1536 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.

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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 does film with a higher ISO.Because digital cameras do not use film, manufacturers have had to create "sensitivity" settings. Some digital cameras only operate at one sensitivity level — others offer sensitivity settings of 100, 200 and 400, to mimic the effects of using film with a speed of 100, 200 or 400. These settings can be very useful; however, because they are achieved artificially, in some cameras they can result in slightly increased noise and color saturation.

Shutter speed
The speed at which a digital camera's shutter exposes the CCD to light. A shutter speed of 1/60 means that a CCD is exposed to light for 1/60th of a second. Faster shutter speeds are good for taking action shots; slow ones 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.

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TIFF
Short for Tagged Image File Format, TIFF is an image file format that does not lose any quality when it is saved and compressed. Many advanced cameras offer a TIFF format option.
Ultra Compact Camera: Ultra compact cameras are generally one inch or less thick, and small enough to be held in the palm of a hand. While these cameras do not offer all the manual controls of larger models, they still are capable of producing high quality images.

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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. For more information, check out our discussion of USB in the Connections Glossary.

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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 on film cameras. A few cameras have an LCD viewfinder, much like a camcorder's viewfinder. A few 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.

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White balance
Electronic adjustment of light levels, which helps recorded images to retain their true colors. Increasingly, digital cameras offer some level of manual white balance adjustment.

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xD-Picture Card
Released in Early 2002 by Olympus and Fuji, xD-Picture Card is the newest digital camera memory format. Physically smaller than all other memory formats, and available (as of 5/03) in sizes up to 256MB, the xD-Picture Card appears poised to replace the older SmartMedia format.

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