Digital Cameras for Teachers
Glossary
Album Album software imports, organizes and catalogs images on a hard drive, usually provides some enhancement and editing tools, and presents photos for printing. Adobe Photoshop Album and Paint Shop Pro Album are among the best album software.
Ambient light The natural light in a scene.
Archival The ability of a material, including some printing papers and compact discs, to last for many years.
Aperture A small, circular opening inside a camera 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 example, 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. See also shutter speed .
Brightness Amount of white available in a color
Buffer Memory in the camera that stores digital photos before they are written to the memory card.
Burning Selectively darkening part of a photo with an image editing program.
Burst mode Digital camera mode that takes a burst of 4-12 pictures in a row. Burst mode can be used in high-speed situations and to compensate for shutter lag.
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 and then converted (outside the CCD, in an analog-to-digital converter) to a digital value.
CD-R CD-Recordable: a compact disc that holds either 650 or 700 MB of digital information, including digital photos. Creating a CD-R is commonly referred to as burning a CD . A CD-R disc can only be written to once, although it can be added to until it is filled up. It is an ideal storage medium for original digital photos.
CD-RW CD-Rewritable: similar to a CD-R, except that a CD-RW disc can be written and erased many times, making it less suited to long term storage of original digital photos.
Click-to-Click Processing “Click to click processing” time is the time a camera takes to process and save the photo to the memory card. This processing time depends on the resolution, if the LCD screen is on, whether use flash is used, and whether that flash is built in or not.
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, except that it performs the conversion to digital as well as recording incoming images on its light sensors. CMOS sensors were originally of low quality but have come back far superior to what they used to be and in some cases outperform CCDs.
CMYK Cyan, Magenta, Yellow, Black. The four colors in the ink wells of many photo-quality printers. Some printers use six ink colors to achieve smoother, more photographic prints. The two additional colors are often lighter shades of cyan and magenta. CMYK is also a pre-press color mode in Photoshop and other photo editing programs. Cyan, Magenta and Yellow are comparable to the primary colors Blue, Red and Yellow, and their complements are Red, Green and Blue, the primary colors of light, as in computer monitors. Cyan, Magenta and Yellow are subtractive, that is, combined they produce an absence of color, or black.
Compact Flash Least expensive type of digital camera flash memory card, about the size of a matchbook. There are two types of cards, Type I, slightly thinner than Type II. A Compact Flash card can also refer to the more expensive miniature hard drive called a microdrive.
Contrast The difference between the darkest and lightest areas in a photo. The greater the difference, the higher the contrast.
Crop Cutting out unwanted parts of a photo from around its edges. A digital zoom will perform this same operation.
Digital camera A camera that captures the photo not on film, but in an electronic imaging sensor that takes the place of film.
Digital Zoom A zoom that in effect crops a picture rather than moving the lens closer to the object of the picture using a physical mechanism. Cameras with digital zoom are usually less expensive than cameras with optical zoom.
Dodging Selectively lightening part of a photo with an image editing program.
Downloading Getting your images into your hard drive. Downloading is usually done by use of USB cables, docks, or USB card readers and software.
DPI Dots per inch: A measurement of the resolution of a digital photo or digital device, including digital cameras and printers. The higher the number, the greater the resolution.
Effective Resolution "Effective Resolution," which reflects the actual number of pixels in the camera's image sensor, is the most important for determining maximum print size.
EXIF Exchangeable Image File: the file format used by most digital cameras. For example, when a typical camera is set to record a JPEG, it's actually recording an EXIF file that uses JPEG compression to compress the photo data within the file.
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. External flash is more easily controlled than built in and automatic flash.
File Extension, File Format The three letters at the end of a document's name that indicate what kind of file it is, whether a jpg, gif, or other type of format.
Fill flash A flash technique used to brighten deep shadow areas, typically outdoors on sunny days. Some digital cameras include a fill flash mode that forces the flash to fire, even in bright light.
Fire Slang for shooting a picture. Example: I pressed the shutter button to fire .
FireWire A type of cable for transferring data to and from digital devices at high speed, usually faster than USB. Some professional digital cameras and memory card readers connect to the computer over FireWire. Also known as IEEE 1394, FireWire was invented by Apple Computer but is now commonly used with Windows-based PCs as well.
Gif Graphics Interchange Format, a lossless graphics format (does not lose quality when compressed) limited to 256 web-safe colors. Gifs are generally used for transparent and flat areas of color such as in cartoons, titles, and animations.
Grayscale A photo made up of 256 shades between black and white. It indicates the absence of color values.
Highlights The brightest parts of a photo.
Histogram A graphic representation of the range of tones from dark to light in a photo. Some digital cameras include a histogram feature that enables a precise check on the exposure of the photo.
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, add filters and effects, and more.
Inkjet A printer that places ink on the paper by spraying droplets through tiny nozzles.
Interpolation "interpolated resolution." It refers to the camera's software adding pixels to the image after it is captured. Interpolated resolution is useful in some cases, but "effective resolution," which reflects the actual number of pixels in the camera's image sensor, is the most important for determining maximum print size and editing flexibility. Be sure you're comparing "effective resolution" when shopping for a camera or you may not get what you are really looking for.
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.
Lossy, Lossless Image formats with high compression algorithms may lose some color data, such as JPEG formats, called Lossy. Repeated saving using lossy formats may degrade a picture irretrievably. Lossless images such as GIF, RAW, PNG and TIFF use other types of compression that preserve color information.
Media Material that information is written to and stored on. Digital photography storage media includes CompactFlash cards and CDs.
Megabyte (MB) A measurement of data storage equal to 1024 kilobytes (KB).
Megapixel Equal to one million pixels.
Memory Stick ® A flash memory card used in Sony cameras.
NiMH Nickel Metal-Hydride: a type of rechargeable battery that can be recharged many times. NiMH batteries provide sufficient power to run digital cameras and flashes.
Online photo gallery A company that reserves space for you to upload and view your images.
Online photo printer A company that receives digital photos uploaded to its Web site, prints them, then sends the prints back by mail or courier.
Optical Zoom Mechanical zoom, or the actual ability of a camera to bring distant pictures closer by moving the lens out of the camera.
Optimizing Balancing download time and quality when deciding whether to print a picture or reduce it in size for emailing or web pages.
Panning A photography technique in which the camera follows a moving subject. Done correctly, the subject is sharp and clear, while the background is blurred, giving a sense of motion to the photo.
Pixel Picture Element: the smallest element of a display that can be assigned a color value. Digital photographs are comprised of thousands or millions of them. The building blocks of a digital photo.
Ppi Pixels per inch
Proprietary Made to a manufacturer's specifications, for example a battery that cannot be used by another manufacturer's camera.
Prosumer A type of digital camera that combines the ease of use of a point and shoot with more advanced SLR features.
RAW The RAW image format is the data as it comes directly off the CCD, with no in-camera processing or compression is performed. Professional photographers prefer high-quality, advanced digital cameras with RAW capacity.
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, outdoor at night, or indoor in a dimly-lit room, causing the eye to dilate and thus allowing the flash to reflect. Some digital cameras compensate for this with a red-eye mode that flashes several times before the photo is taken, causing the pupil of the eye to close.
Resize Reducing size and resolution in order to make an image small enough to email or put on a website. Usually images cannot be successfully resized to larger sizes.
Resolution - The number of pixels in a digital photo is commonly referred to as its image resolution. This term refers to the quality and clarity of an image. In the digital world it is usually referred to in terms of pixels. For printing, pixels per inch is the measurement (sometimes also "dots per inch," though the two are not identical in meaning). In the case of cameras, megapixels is the measurement. Resolution is the one of the most important aspects of any digital camera purchase, and is a rough guide to how much a camera will cost.
RGB Red, Green, Blue: the primary colors of light and thus the primary colors of computer monitors, cameras, and the human eye. RGB is "additive" color, meaning all three colors combined adds up to white. Complementary colors to RGB are CMY, Cyan, Magenta, and Yellow, the primary pigment colors.
Saturation How rich the colors are in a photo; the depth and intensity of the hue.
Secure Digital Flash memory card used in Kodak, Nikon, HP, Vivitar, and other digital cameras. SDs are also used in HP PDAs.
Sharpness The clarity of detail in a photo. Photos maybe sharpened using photo editing software, although too much sharpening can result in grainy pictures.
Shutter Lag One of the banes of digital photography. Shutter lag is the time it takes for the camera to set up the shot automatically for you, and in the process you may miss making the shot. Newer, faster cameras have addressed this problem. There are workarounds for older cameras, including holding down the shutter half-way until you're ready to take the picture, and using the Sports Mode or Burst Mode.
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. See also aperture .
Single Lens Reflex, SLR In film photography, a single lens reflex camera allows you to look through the viewfinder and see what the lens sees. This is not true of range finder cameras, which do not see through the lens. SLR cameras generally allow lenses to be swapped out. Recent digital cameras are approaching SLR cameras in quality.
Smart Media a wafer-thin, matchbook size flash memory card.
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.
Tiff Tagged Information File Format, usually a lossless format. Tiffs are large files used in printing CMYK.
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.
White balance A digital camera can compensate for the difference in natural and artificial light such as fluorescent and incandescent light by use of its White Balance settings .
xD memory Flash memory in a very small size, used mainly in Olympus and Fuji cameras. xD memory tends to be more expensive than other types.
Digital Cameras for Teachers
EOU Malheur County Center (541) 889-7468 or (541) 889-6222
