A
aberration A distortion in an image caused by a flaw in a mirror or lens.
achromatic color A color with no saturation, such as light gray.
acquire A software menu selection to scan from within the program (if it is TWAIN compliant).
ADC (analog-to-digital converter) A device that measures electrical voltages and assigns digital values to them.
Airy disc A disc of light caused when a pinpoint of light is diffused to form concentric halos about the original point.
aliasing The noticeable repeated patterns, lines, or textures in any photographed or scanned subject that conflict with the pattern of an electronic sensor’s pixel arrangement. For example, diagonal lines represented by square pixels will produce jagged lines.
analog The measurement and recording of continuously varying values in the real world, such as sound, light, and size. The measurements correspond proportionally to other values, such as electrical voltage. Film cameras are analog devices.
anti-shake One of several technologies to counteract the movement of a lens and the resulting
blurring of a photo.
antialiasing A technique of blending variations in bits along a straight line to minimize the stair-step or jagged appearance of diagonal edges.
aperture The lens opening through which light passes, expressed by a number called the f-number (or f-stop). Typically, f-stops range from f-2 through f-32, although many lenses don’t reach the extremes on either end. Each higher number represents an opening half the size of the previous number, with f-2 being the largest opening and f-32 the smallest. The aperture is one of the key factors in an exposure setting.
array A grouping of elements, such as the rectangular array of photodiodes that make up the digital film that captures an image.
artifact An unwanted pattern in an image caused by the interference of different frequencies of light, from data-compression methods used to reduce the file size, or from technical limitations in the image-capturing process.
aspect ratio The ratio of length to width in image sensors, computer displays, television screens, and photographic prints.
autofocus A lens mechanism that automatically focuses the lens by bouncing an infrared light beam or sound waves off the subject matter or by measuring the contrast in a scene. Some cameras use a combination of methods.
automatic exposure A camera mode that adjusts both the aperture and shutter speed based on
readings from a light meter.
automatic flash An electronic flash that measures the light reflected from a subject, varying the duration and intensity of the flash for each exposure.
available light All the natural and artificial light a photographer uses, short of light provided by flash units. Or as one photographer put it, all the light that’s available.
B
back-lit or back-lighting A setting that illuminates the subject from behind.
banding Areas of color that show no differentiation except to change abruptly from one color intensity to another so that what should be a gradual change of color is marked by noticeable bands of color.
Bayer pattern, Bayer matrix A distribution of red, green, and blue filters on an image sensor
that provides twice as many green filters as red and blue because of the eye’s sensitivity to shades of green.
bit depth The number of bits—0s and 1s in computer code—used to record, in digital image situations, the information about the colors or shades of gray in a single pixel, which is the smallest amount of information in a graphic image. The smaller the bit depth number, the fewer tonal values possible. For example, a 4-bit image can contain 16 tonal values, but a 24-bit image can contain more than 16 million tonal values.
bitmap An image represented by specific values for every dot, or pixel, used to make up the image.
black noise Also known as dark current, it is the signal charge the pixel develops in the absence of light. This charge is temperature sensitive and is normal in electrical image-sensing devices.
bleeding The color value of one pixel unintentionally appearing in the adjacent pixel or pixels.
blooming The bleeding of signal charge from extremely bright pixels to adjoining pixels, oversaturating those adjoining pixels. Masks or potential barriers and charge sinks are used to reduce blooming.
BMP file A Windows file type that contains a bitmapped image.
borderless printing A printing technique, offered on some photo printers, that prints photos from paper’s edge to paper’s edge, without leaving a white border.
bounce flash Light bounced off a ceiling, wall, or other surface to soften the light hitting a subject and eliminate the harsh shadows that often result from a flash aimed straight at the subject.
bracket A burst mode that, as a safety precaution, shoots extra exposures that are normally one f-stop above and below the exposure indicated by the light meter reading.
brightness One of the three dimensions of color—hue, saturation, and brightness. Brightness is the relative lightness or darkness of a color, ranging from 0% black to 100% white.
burst mode The capability of a camera to take several pictures one after another, as long as the shutter button is depressed or until the memory buffer is full. The size of the memory buffer and the speed that the camera writes the data to a memory card determine the burst rate.
C
calibrate To adjust the handling of light and colors by different equipment, such as cameras,
scanners, monitors, and printers, so the images produced by each are consistent to a defined
standard of brightness, hue, and contrast.
catchlight Light that reflects from a subject’s eyes and adds life to the portrait.
charge-coupled device (CCD) An image sensor made up of millions of photodiodes, which are transistors that convert light energy to electrical energy and transmit the electrical charges one row at a time.
chroma A quality of color combining hue and saturation.
circle of confusion Points of light focused by the lens into discs of light. The smaller the circles of confusion (the discs), the sharper the image appears.
clipping The loss of color information above or below certain cutoff values.
CMOS image sensor An image sensor similar to a CCD but created using CMOS technology.
CMOS stands for complementary metal-oxide semiconductor.
CMYK (cyan, magenta, yellow, black) Often called process color; a color model used to
optimize images for printing in which all colors are produced by combinations of these four colors. Inkjet, laser, dye-sublimation, thermal wax, and solid ink printers use CMYK as their primary colors. This creates a color-management problem on computers because converting the native colors of computing—red, green, and blue—to CMYK files causes color shifts.
color, additive The creation of colors in cameras, monitors, and scanners by combining the
effects of pixels colored red, blue, and green, usually referred to as RGB.
color, subtractive A system such as printing that creates colors by combining the absorption
capabilities of four basic colors: cyan, magenta, yellow, and black.
color balance The overall accuracy of the hues in a photograph, particularly with reference to
white.
color depth The number of bits assigned to each pixel in the image and the number of colors that can be created from those bits.
color fringing A digital-imaging artifact caused when color-filtering arrays or patterns of photodiodes on image sensors conflict with visual information in a scene, causing discolorations along the edges of some objects.
color intensity The brightness of a printed image controlled by the amount of ink applied to the page; lighter images use less ink and darker images use more.
color management system (CMS) Software utilities to calibrate color on input and output
devices like displays, printers, and scanners. Color management systems control the accurate conversion of colors from RGB to CMYK.
color temperature The warmth or coolness of light, measured in degrees Kelvin (K). Mid-day
daylight is about 5,500K. Light bulbs are about 2,900K, meaning they’re more orange or warm. Color temperature is important to color balance.
CompactFlash memory Based on Personal Computer Memory Card International association
(PCMCIA) PC card specifications, CompactFlash measures 43mm ◊ 36mm and is available with storage capacities exceeding 8GB. Currently, the competition among CompactFlash makers is to produce cards that do a faster job of writing (saving) and reading (retrieving) data. Speeds are expressed as a multiple of basic speed of the original CompactFlash (1X). Current speeds read as much as 150X.
compression, lossless A file compression scheme that makes a file smaller without sacrificing
quality when the image is later uncompressed. Zip and GIF files use lossless compression.
compression, lossy A file compression scheme that reduces the size of a file by permanently
discarding some of the visual information. JPEG is the most common lossy compression format for graphics.
compression ratio The ratio of the size of a compressed digital file to the original uncom-
pressed file. Ratios between 15:1 and 8:1 are the most often used in digital cameras. Highest quality ratios are less than 5:1, non-lossy compression is 2:1 or less.
continuous tone An image, such as a film photo, that has a gradual range of tones without any
noticeable demarcation from one to the other.
contrast The difference between the dark and light areas of an image.
cropping An image editing technique that removes parts of the photo along the sides to eliminate unwanted details.
D
demosaic An algorithm used to fill in missing color information from an image captured by a
camera’s mosaic sensor.
density The capability of a color to stop or absorb light; the more light absorbed or the less light reflected, the higher the density.
depth of field The area between the nearest and farthest points that are in focus through a camera lens. Depth of field increases at smaller lens apertures.
Design Rule for Camera File System (DCF) An industry standard for saving digital images.
This not only determines the file type, but also sets the rule for naming the folder and file structure. It allows the conversion of uncompressed TIFF files into compressed JPEG files.
diaphragm (Also iris.) A mechanism located in a lens that controls how much light passes
through the lens. It is typically made of overlapping, interlocked leaves that form a roughly circular opening in the center of the diaphragm. When the exposure ring on the lens is twisted, the leaves contract or expand to allow more or less light through.
diffuser A translucent plastic or cloth placed between a flash and the subject. The diffused light softens shadows and contrast.
digital The measurement and recording of continuously varying values such as sound and light by frequently sampling the values and representing them with discrete numerical values, usually expressed as binary numbers.
dithering The process of creating different colors by placing dots of ink coloring near each other in different combinations to create the illusion of other colors.
dots per inch (dpi) A measurement of resolution used for scanning and printing.
dye-sublimation printer The printing system that transfers colors from ribbons containing dyes that are heated and fused onto paper. Dye-sublimation printers are continuous-tone printers capable of producing photographic quality images.
dynamic range The range of the lightest to the darkest areas in an image. Its value is expressed as the ratio of contrast, tonal range, or density in an image between black and white. The number 0.0 represents white, and 4.0 is black. A flatbed scanner may have a dynamic range of 2.4–2.7 whereas a drum scanner may be as high as 3.6–3.8. The numeric ranges express the capability of the devices to record and reproduce the range of grays between black and white. The higher the number, the greater the detail in shadows and highlights in an image. Film is generally given a dynamic range of 4.0; most digital cameras and scanners range from 2.4–3.0. Dynamic range may also refer to the ratio of the maximum signal level a system can produce compared to its noise, or static, level. Also known as signal-to-noise ratio.
E–F
entrance pupil A virtual representation of a lens’s aperture opening, the entrance pupil is a measure of the angles that light will take on its passage through the aperture. It is of more practical consideration in the shooting of panoramic photos, which are often taken as several shots using a camera that pivots to take in the wide vista that is later pieced into a single wide photograph. A hazard in panoramic photos is parallax error, caused when the camera does not pivot correctly about its center of perspective. The error can cause an object as immobile as a fence post to appear twice in the same photo, seemingly in different positions. To avoid parallax error, the camera must pivot on its center of perspective, which coincides with the entrance pupil. (Writings on panoramic photography often erroneously identify the center of perspective as a lens’s nodal point.)
EXIF (exchangeable image file) A file storage format used for images on flash memory cards
and digital cameras. EXIF files contain either JPEG compressed files or uncompressed TIFF files along with extensive information about a camera’s settings when a photo was taken.
exposure The amount of light used in a photograph, based on the aperture and how long the
shutter stays open.
exposure compensation The capability to automatically change exposure by one or more
stops to lighten or darken the image.
filter A mathematical formula applied to a digital image. Most image editors offer filters to correct flaws in exposure, color, sharpness, and other blemishes.
fish-eye lens An extremely wide-angle lens that can take in a view as wide as 180°. The result is often a circular image.
fixed focus A lens made to permanently focus on the most common range, from a few feet to
infinity. The focus is usually not as sharp as that obtained with a variable focus lens.
flash A short, brilliant burst of light.
flash, fill Flash used to fill shadows caused by overall bright lighting.
flash, high-speed In ordinary flash photography, the flash is synchronized to fire when the first
shutter curtain is fully open and before the second curtain starts to close. High-speed sync extends the flash duration, making flash synchronization possible when using fast shutter speeds that form a slit between the first and second curtains when they are opening/closing simultaneously.
flash, modeling A longer flash fired before photographs are taken to determine how the place-
ment of the flash will affect light balance and shadows.
flash, multiple A lighting setup using several flash units that may be wired to the same camera, or that are activated by radio signals or by the burst of light from a central flash gun.
flash, pre- (preflash) A low-output flash fired before the main flash to measure the distance to
the subject and to calculate how the main flash should be fired to create a correct exposure.
flash, slave A flash unit that fires in response to the firing of a master flash unit.
flash, slow-sync mode To better expose in a night shot the background beyond the range of a
flash unit, slow-sync holds the shutter open long enough to capture more of the background before firing the flash to expose the main subject in the foreground.
flash, stroboscopic A series of individual flashes fired quickly while the shutter is open, capturing multiple exposures on a single frame. Stroboscopic flash is effective for capturing movement against a dark background.
flash, x-sync An electrical setting that makes the flash fire when the shutter is fully open. In SLR cameras equipped with a focal-plane shutter, the x-sync speed is the fastest shutter speed at which the first and second shutters are fully open.
flash exposure compensation A flash unit adjustment that changes the amount of light the
flash provides to fine-tune the balance between foreground and background exposure.
flash memory card A card containing chips that store images using microchips instead of
magnetic media.
flash synchronization Firing of the flash as the shutter curtains open and close so that the
scene will be evenly lit.
focal length The distance, in millimeters, from the optical center of the lens to the image sensor when the lens is focused on infinity. Also defined as the distance along the optical axis from the lens to the focal point. The inverse of a lens’s focal length is called its power. Long focal lengths work like telescopes to enlarge an image; short focal lengths produce wide-angle views.
focal point The point on the optical axis where light rays form a sharp image of a subject.
focusing Adjusting a camera’s lens system to bring the subject into sharp view.
formatting Completely erasing and resetting a camera’s memory card so that it can accept new photos.
G–H
gamma A mathematical curve created by the combined contrast and brightness of an image,
which affects the balance of the middle tones. Moving the curve in one direction makes the image darker and decreases the contrast. Moving the curve in the other direction makes the image lighter and increases the contrast. The blacks and whites of an image are not altered by adjusting the gamma.
gamma correction Changing the brightness, contrast, or color balance by assigning new values to the gray or color tones. Gamma correction can be either linear or nonlinear. Linear changes affect all tones, non-linear changes affect limited areas tone by tone, such as highlights, shadows, or mid-tones.
gamut The range of colors a device captures or creates. A color outside a device’s gamut is
represented by another color that is within the gamut of that device.
GIF (Graphics Interchange Format) A compressed image format. GIF was the first commonly used image format on the Web, but it has been largely replaced by JPEG.
gigabyte (GB) A unit of data equal to 1,024 megabytes.
grayscale At least 256 shades of gray from pure white to pure black that represent the light and dark portions of an image.
guide number A number keyed to the amount of light a flash emits. The number, divided by
the aperture setting, provides the distance to the subject for the optimum exposure. Divided by the distance to the subject, the number yields the correct aperture setting.
histogram A graph showing the distribution of light and dark values throughout a photograph,
roughly equivalent to a photo’s dynamic range.
hot shoe A clip on the top of the camera to which you can attach a flash unit; it includes an electrical link to synchronize the flash with the camera.
HSB The color model that most closely resembles the human perception of color. It is made up of 160,021,403,206 colors.
hue One of the three dimensions of color. (The others are saturations and brightness.) Hue is the wavelength of light reflected from or transmitted through an object, seen in the visible spectrum. Red, yellow, blue, and so on are the names of the hues.
I
IEEE 1394 A personal computer port capable of transferring large amounts of data at high
speeds, often used to upload graphic and video files. It’s known as i.Link on Sony systems and
FireWire on Apple computers.
image editor Software to edit and modify digital images. With an image editor, you can add
special effects and fix certain composition problems, as well as add new elements to the image.
image sensor A microchip that records images by converting the scene’s light values into an
analog electrical current that travels to a memory chip to be recorded as digital values.
intensity The amount of light reflected or transmitted by an object, with black as the lowest
intensity and white as the highest intensity.
intermittent flash Simulating a longer-lasting flash by repeatedly firing the flash unit(s) at high speed. Intermittent flash is used for high-speed sync and modeling flash.
interpolation A process used in digital zooms and digital darkrooms to enlarge images by creating the new pixels. This is done by guessing which light values they should have based on the values of the original pixels in the image that would be next to the new ones.
interpolation, bicubic Two-dimensional cubic interpolation of pixel values based on the
16 pixels in a 4- ◊ 4-pixel neighborhood.
interpolation, bilinear An enlargement in output pixel values is calculated from a weighted
average of pixels in the nearest 2 ◊ 2 neighborhood.
interpolation, nearest neighbor An enlargement by copying pixels into the spaces created
when the original pixels are spread apart to make a bigger image, just like film grains under an
enlarger.
ISO Named after the organization that defined this standard, it’s a numerical rating that indicates the relative sensitivity to light of an image sensor or photographic film. A higher ISO number represents a greater sensitivity to light and requires less exposure than a lower ISO number does.
J–K–L
jaggies The stair-step effect in diagonal lines, or curves that are reproduced digitally.
JPEG Also known as JPG and .jpg, it’s a popular digital camera file format that uses lossy compression to reduce file sizes. It was developed by the Joint Photographic Experts Group.
JPEG-2000 A JPEG compression standard that uses a totally different approach to compression to obtain a higher compression ratio without losing image quality. Created specifically for digital cameras and imaging software, it was supposed to become the new standard starting in 2001, but it is still far from universal among digital cameras. A JPEG-2000 file typically has an extension of .jp2.
lag time The time between pushing the shutter button and when the exposure is made by the
camera.
LCD A liquid crystal display is the most prevalent technology used on digital cameras to view and preview digital photos.
lithium-ion batteries A long-lasting, rechargeable battery technology used in digital cameras;
lithium is the lightest metal and has the highest electromechanical potential.
long lens A telephoto lens.
M
macro mode A lens mode that allows focusing on objects only inches away.
main flash The flash fired after the preflash when the shot is actually taken.
megapixel An image or image sensor with about one million pixels.
memory card (Also flash memory.) A removable microchip device used to store images by
most digital cameras. Unlike a computer’s RAM, this card retains data even without electricity. Six main types of memory cards are in use today: CompactFlash, SmartMedia, Secure Digital, Memory Stick, Multimedia Cards (MCC), and xD Picture Cards.
memory card reader A computer component or an attachment that reads the image data on a
card and sends it to the computer.
Memory Stick A flash memory storage device shaped like a stick of gum, developed by Sony,
that can hold up to 8GB of data.
metering, autoflash Measurement of light that occurs when a light sensor meters the light
reflected by a subject after the flash begins firing. The flash output is then controlled instantly so that the subject is exposed properly.
metering, center-weighed A light reading that emphasizes the intensity of light reflected from
objects in the center of the viewfinder’s frame.
metering, matrix A light meter reading produced by reading the light from several areas
throughout the frame.
metering, spot A light reading taken of a narrow area, smaller than that used in center-
weighted metering, usually in the center of the frame.
midtones Light values in an image midway between the lightest and darkest tones.
MPEG A digital video format developed by the Motion Picture Expert Group.
N–O
NiCad batteries (also nicad and NiCd) Once a serious improvement over common
alkaloid-based batteries, nickel cadmium batteries are losing favor because they must be recharged frequently.
NiMH batteries Rechargeable nickel metal hydride batteries store up to 50% more power than NiCad batteries.
nodal points The front nodal point in a compound lens is where rays of light entering the lens
appear to aim. The rear nodal point is where the rays of light appear to have come from after passing through the lens. The nodal point (singular) is often wrongly cited as the point around which a camera should rotate to avoid parallax error. The correct point is the entrance pupil.
noise A random distortion in an analog signal causing dark or colored flecks in an image, particularly in dark areas. It can be caused by electronic noise in the amplifiers that magnify the signals coming from the image sensor, nearby electrical spikes, heat, or other random electrical fluctuations. Noise is more prevalent at higher ISO levels.
normal lens A lens with about the same angle of view of a scene as the human eye—about 45°.
optical character recognition (OCR) A scanning technology that recognizes letters and translates them into text that can be edited onscreen.
P–Q
panorama An exceptionally wide photograph. Generally, they are expected to have about the
same field of view as the human eye—about 75° vertically by 160° horizontally—although there are no hard and fast standards. Some panoramas encompass a 360° horizontal view. Whatever the view, a panorama is expected to retain details that you would not get by simply cropping and enlarging a photo with a normal aspect ratio. Panoramas may be produced by specialized cameras, or segmented panoramas may be created by using software to stitch together several normal photographs that by themselves contain only parts of the final vista.
parallax A composition error caused by the discrepancy between view fields of an optical
rangefinder and the lens. Also caused by pivoting the camera incorrectly while taking a segmented panorama.
photodiode A semiconductor device that converts light into electrical current.
PictBridge An industry open standard that allows photos to be printed directly from digital cameras connected to a printer without an intervening PC.
pixel A picture element, the smallest individual element in an image.
pixelation An effect caused when an image is enlarged so much that individual pixels are easily seen.
pixels per inch (PPI) A measurement of the resolution of an image based on the number of pixels that make up 1 inch.
plug-in A software module that adds new capabilities to imaging programs such as Adobe
Photoshop and Paint Shop Pro.
preview screen A small LCD screen on the back of a camera used to compose or look at
photographs.
prime lens A lens whose focal length is fixed, as opposed to a zoom lens, which has a variable
focal length. Prime lenses are not as versatile as zooms; often they cost less and yet have better
optics because it’s easier to optimize optics for a single focal length.
R
RAW format The uninterpolated data collected directly from the image sensor before processing.
red eye An effect that causes eyes to look red in flash exposures; it’s caused by light reflecting off the capillary-covered retina.
red-eye Reduction mode A mechanism that fires a preliminary flash to close the iris of the eye before firing the main flash to take the picture.
resolution The sharpness of an image that’s measured in dots per inch (dpi) for printers and pixels per inch (ppi) for scanners, digital cameras, and monitors. The higher the dpi or ppi, the greater the resolution.
resolution, interpolated A process that enlarges an image by adding extra pixels whose color
values are calculated from the values of the surrounding pixels.
RGB The acronym for red, green, and blue, which are the primary colors of light and also the
color model used for television, digital cameras, and computer monitors.
rule of thirds A rule in composing pictures that divides the frame into nine equal areas. The main objects in the photos should be aligned along one of the lines or at an intersection.
S
saturation The amount of color in a specific hue. More saturation makes the colors appear more vivid, whereas less saturation makes the colors appear muted.
Secure Digital memory A memory card about the size of a postage stamp. It weighs about
two grams; available with storage capacities as high as 4GB.
sharpening A function in digital darkroom software, some cameras, and some scanners that
increases the apparent sharpness of an image by increasing the contrast of pixels along the borders between light and dark areas in the image.
shift-tilt lens A lens with a mechanism that lets part of it shift in any direction parallel to the camera’s image plane or tilt in any direction. Shifting the lens is used to correct perspective distortions, particularly in architectural photography, caused when the camera is tilted, for example, at ground level to take in the entirety of a tall building. Tilting the lens changes the depth of field area that’s in focus so that it is on a diagonal in relation to the camera, allowing the photographer to bring into focus more elements that are stretching away from the camera.
short lens A wide-angle lens that includes more of the subject area.
shutter The device in a camera that opens and closes to let light from the scene strike the image sensor and expose the image.
shutter speed The length of time during which the camera shutter remains open. These speeds
are expressed in seconds or fractions of a second, such as 2, 1, 1/2, 1/4, 1/8, 1/15, 1/30,
1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000, and 1/8000. Each increment is equal
to one full f-stop. Increasing the speed of the shutter one increment, for example, reduces the amount of light let in during the exposure by half, so the lens aperture would need to be opened one f-stop to produce an exposure with the same tonal values as the exposure made with the original shutter speed setting.
shutter-priority mode An automatic exposure system in which you set the shutter speed and
the camera selects the aperture (f-stop) used to make the exposure.
SmartMedia A memory card developed by Toshiba that uses flash memory to store data. It measures 45mm ◊ 37mm and is less than 1mm thick. Available in capacities to 128MB.
softbox A lighting enclosure that includes one side fitted with a material that diffuses light to
make lighting and shadows cast by it seem less harsh. The larger the diffusing surface, the softer the lighting.
Speedlite and Speedlight Trademarked terms for flash units made, respectively, by Canon and
Nikon.
T
thermal wax printer Like a dye-sublimation printer, thermal wax printers transfer colors from RGB, CMY, or CMYK ribbons containing waxes, which are warmed and fused onto special papers. These printers generally have excellent imaging quality with poor text quality.
threshold A color or light value of a pixel before software or a camera does anything with the
pixel’s information. For example, blue values might be substituted with red values, but only if the blue pixels have an intensity within a certain range of values. The higher the threshold, the fewer pixels affected.
thumbnail A small image that represents a bigger version of the same picture.
TIFF tagged image file format A popular lossless image format used by professional photographers and designers. It is also the most common format for scanned images.
TWAIN An industry-standard method for allowing a scanner to communicate directly with image editing software or a word processor.
U–V
umbrella Literally, just what it sounds like it is. But in studio photography, umbrellas may be much larger than the ones used to ward off rain, and they are made of a white material that diffuses light passing through it. Studio light may be aimed into the “underside” of an umbrella so light passes through the material to cast a soft light on the subject. Or, the underside may be pointed toward the subject, and the light is then reflected off the concave surface to achieve much the same effect.
upload variable-focus Sending files from a device, such as a digital camera or memory card, to a computer. A lens whose range of focus can be changed from a close distance to infinity.
viewfinder, optical but only approximately.
viewfinder, single-lens reflex lens that will be used for taking the picture.
viewfinder, TTL (through-the-lens) image produced by the lens to create a photograph.
A separate window that shows what would be included in a photograph.
A viewfinder whose image comes directly through the same.
A viewfinder that looks through the lens to use the same.
W–X–Y–Z
white balance An automatic or manual control that adjusts the brightest part of the scene so it
looks white.
white point The color that is made from values of 255, each for red, blue, or green in a camera’s sensor image, a monitor, or a scanner. On paper, the white point is whatever color the paper is.
wide-angle lens A lens with an angle of view between 62° and 84°.
xD Picture Card Weighing 2.8 grams and not much bigger than a penny (20mm ◊ 25mm ◊
1.78mm), the xD Picture Card is used in Olympus and Fuji digital cameras. There are two types of xD cards, M and H. Type H is the newer and faster of the two.
zone system A method developed by photographer Ansel Adams for setting exposure compensation by dividing the entire grayscale range in 11 zones from 100% white to 100% black.
zoom, digital A way of emulating the telephoto capabilities of a zoom lens by enlarging the center of the image and inserting new pixels into the image using interpolation.
zoom, optical A method that changes the focal length of a lens to change its angle of view from wide angle to telephoto. Optical zoom is preferable to digital zoom.
zoom lens A lens that lets you change focal lengths on-the-fly
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