A

Accessory Shoes - seed "Hot Shoe".

Aberration
A distortion of image quality or color rendition within a photographic image caused by optical limitations of the lens used to produce the image. Aberrations commonly show up in the form of halation around contrasty portions of the image and/or 'smearing' of color toward the edges of the frame.

Absolute resolution
Image resolution as expressed in horizontal versus vertical pixels. (E.g. 1600x1200 Pixels is the absolute resolution, and is also expressed as 2.1 Megapixel)

Adobe RGB
A widely accepted color space that encompasses a wider range of color than the more commonly used sRGB color space. Adobe RGB is the preferred color space for images intended for prepress applications

AE (Automatic Exposure)

AE-L (Automatic Exposure Lock)
Auto exposure Lock. Metering feature that used to hold the exposure setting when used in the automatic mode. Used most commonly in situation where off centering of the subject in composition and wish to retain the exposure setting of the subject OR where the level of exposure reading both the subject of interest and the background exposure reading is different eg. back lighting. Used to hold an automatically controlled shutter speed and/or aperture. Recommended when the photographer wants to control an exposure based on a scene's particular brightness area with Center Weighted or Spot Metering.

AF Servo
A.k.a. Continuous Focus, AF Servo, is maintained by partially pressing the camera's shutter release button, which enables you to maintain focus on a moving subject as the subject moves within the frame. Shutter response times are usually faster in AF Servo since the subject is already in focus.

Aliasing
The process by which smooth curves and lines that run diagonally across the screen of a low-resolution digital file take on a 'jagged' look as opposed to a smooth, natural rendition. Smoothing and anti-aliasing techniques can reduce the effect of aliasing.


Ambient light – The natural light in a scene.

Aperture – A small, circular opening inside the 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 instance, 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 to your own liking. See also shutter speed.

Aperture Priority
A metering mode in which the photographer sets the desired lens aperture (f-stop) and the camera in turn automatically sets the appropriate shutter speed to match the scene being recorded. Portrait photographers usually prefer wider apertures, while landscape photographers prefer smaller apertures, regardless of the lighting conditions. Aperture priority is a preferred method to maintain a fixed degree of depth-of-field while shooting under rapidly changing lighting conditions.

Aperture ring
A ring, located on the outside of the lens usually behind the focusing ring, which is linked mechanically to the diaphragm to control the size of the aperture; it is engraved with a set of numbers called f-numbers or f- stops.

APS-C (APSC)
A term used to describe the size of a digital camera sensor with a 1.5x magnification factor. The name is derived from the APS (Advanced Photo System) film format that was introduced in 1996 for the amateur point-and-shoot market. The APS format is 50% smaller than a standard 35mm frame. All Nikon, Pentax, Fuji , and Sony (Alpha) DSLRs contain APS-C sized imaging sensors. Canon's EOS Rebel-series, 20D, and 30D DSLRs are also described as containing APS-C sized sensors even though their sensors are about 20% smaller (1.6x).

Artifact
Artifacts refer to distortions within the image as a result of image compression or interpolation. Artifacts can be seen as light halos around dark areas of an image or as 'blockiness' of a highlight area of an image. Forms of artifacts include blooming, chromatic aberrations, 'jaggies', moiré, noise, and halation.

Auto Exposure Bracketing:
Auto Exposure Bracketing performs automatic exposure bracketing with varied shutter speed and/or aperture.

Autofocus (AF)
System by which the camera lens (most popular) or the camera body (only available in Contax AX) automatically focuses the image of a selected part of the picture subject. The autofocus camera revolution first popularised with the launch of Minolta's Maxxium. Currently, most current SLRs are autofocus based.

AV
The Aperture value, usually refer to aperture settings.




B

B (Bulb) Setting
A shutter-speed setting on an adjustable camera that allows for time exposures. When set on B, the shutter will stay open as long as the shutter release button remains depressed. Another similar option is the "T" setting, where it never drains the battery power on automatic camera body.

Background
The part of the scene the appears behind the principal subject of the picture. The sharpness of the background can be influenced by apertures and shuttle set. In the flash mode, bulb setting usually is set for absorbing more ambience light (background information), so the end result of the exposure won't be pitch dark.

Backlighting
Light coming from behind the subject, toward the camera lens, so that the subject stands out vividly against the background. Sometimes produces a silhouette effect. Always use something (a hand, a lens shade to avoid the light falls onto the lens - to avoid lens flares).


Barrel Distortion
An optical distortion in which the image 'bows' out of square. Barrel distortion is usually associated with less-expensive wide-angle lenses and digicams, and is most apparent in architectural photographs or images containing lines that run parallel to each other in the horizontal or vertical plane.

Batch Scan
The ability to scan and process more than one image in a single action.

Bit
A bit (binary digit) is the smallest unit of digital information. Eight bits equals one byte. Digital images are often described by the number of bits used to represent each pixel. I.e. a 1-bit image is monochrome; an 8-bit image supports 256 colors or grayscales; while 24 or 32-bit supports an even greater range of color.

Bitmap
A method of storing digital information by mapping out an image bit by bit. The density of the pixels determines how sharp the image resolution will be. Most image files are bit mapped. Bitmap images are compatible with all types of computers.

Blocked Shadows
Term for lack of, or loss of, shadow detail in a photographic image, usually the result of underexposure or lower resolution (and less dynamic) imaging sensor. Can sometimes be partially corrected in Photoshop or similar photo editing applications.

Blooming
The appearance of a bright or colored halo around brighter areas of digital image files. Blooming is caused when a portion of the imaging sensor in a digital camera is exposed to too much light, causing signal "leaks" to the neighboring pixels.
*Also see Chromatic Aberration.

Blowout
Blowout is caused by overexposure, which results in a complete loss of highlight details. With the exception of RAW files captured within 2-stops of the correct exposure, 'blown' highlights are difficult, if not impossible, to correct after the fact.


Blowup
An enlargement; a print that is made larger than the negative or slide.

Bounce Lighting
Flash or tungsten light bounced off a reflector (such as the ceiling or walls) or attachment that fits on the flash (like the LumiQuest's Pocket Bouncer) to give the effect of natural or available light.

Bracket flash
Often called handle mount flash. It comprised of one arm of the L-shaped bracket extends under the camera body and uses the camera's tripod socket to mount the camera on the bracket. The vertical arm of the bracket serves as a handle and mounts a flash unit in an accessory shoe often on top of the handle portion, but there are other methods. Flash mounted in a bracket usually requires a separate electrical cord to make the electrical connection between camera body and flash unit.

Bracketing
Taking a series of photographs of the same subject at different exposures to insure the "correct" exposure; useful when shooting in situations where a normal metering reading is difficult to obtain. Taking additional pictures of the subject through a range of exposures-both lighter and darker-when unsure of the correct exposure.Some top cameras have provision for automatic bracketing, while manually you can bracket by the use of, say, adjust apertures or shuttle speeds setting or both, manually influent the ASA setting or even adjust the flash output power etc..

Buffer – Memory in the camera that stores digital photos before they are written to the memory card.

Buffer Memory
Memory that is built into a device such as a printer or camera that temporarily holds the data until the device can process and/or transfer the information to a memory card or other storage device.

Burning-In
Basically, a darkroom process that gives additional exposure to part of the image projected on an enlarger easel to make that area of the print darker. This is accomplished after the basic exposure by extending the exposure time to allow additional image-forming light to strike the areas in the print you want to darken while holding back the image-forming light from the rest of the image. Sometimes called printing-in.

BMP
A bit-mapped file format used by Microsoft Windows. The BMP format supports RGB, indexed-color, grayscale, and Bitmap color modes.

Bulb
Flashbulbs - A special flashbulb that can be used at certain shutter speeds is called "FP" where the initials stand for Focal Plane. Designed for use with focal-plane shutters these bulbs make a nearly uniform amount of light for a relatively long time. The idea is to turn on the light before the focal-plane shutter starts to open and keep the light on until the shutter is completely closed. Firing delay for flashbulbs is indicated by code letters: "F"- fast; "M"- medium; "MF" - mediurn fast; "S" - slow

Burst Rate
The number of consecutive images a digital camera can capture continuously before filling the buffer memory.



C

CA- Creative Auto

Candid Pictures
Unposed pictures of people, often taken without the subject's knowledge. These usually appear more natural and relaxed than posed pictures.

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, then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.

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. CMOS sensors are currently found in only a handful of digital cameras.

CMYK – Cyan, Magenta, Yellow, Black. The four colors in the inksets 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.

Chromatic aberration
A lens aberration producing an overall blurred image; the inability of a lens to bring all wavelengths of light (especially red and blue) into the same plane of focus; usually present in regular large-aperture telephoto and super-telephoto lenses; does not improve by stopping down the lens; correctable through the use of Iow Dispersion (ED, LD SD) glass. Basically, this aberration is caused by light rays of different wavelengths coming to focus at different distances from the lense. Blue will focus at the shortest distance and red at the greatest distance. Since the natural rays of light are a mixture of colors, each aberration will give a different value corresponding to each color thus producing blurred images.

Coated Lens
A lens covered with a very thin layer of transparent material that reduces the amount of light reflected by the surface of the lens. A coated lens is faster (transmits more light) than an uncoated lens.

Color Calibration
A process by which the image source (digital camera or scanner), monitor, and output (printer) are matched to use the same or similar color palette. This insures that the image viewed on the monitor has the same range of colors as the image that is printed, and any adjustments made to the color of the image in the computer are accurately represented when the image is printed.

Color Depth
The number of distinct colors that can be represented by a piece of hardware or software. Color depth is sometimes referred to as bit depth because it is directly related to the number of bits used for each pixel. A 24-bit Digital Camera, for example, has a color depth of 2 to the 24th power (about 16.7 million) colors.

Color Management
A system of coordinating and calibrating the color responses of digital cameras (or scanners), monitors, and printers to ensure the color and tonal values of the image you see on the screen matches the final print image.

Color Palette
A palette is the set of available colors. For a given application, the palette may be only a subset of all the colors that can be physically displayed. For example, many computer systems can display 16-million unique colors, but a given program would use only 256 of them at a time if the display is in 256-color mode. The computer system's palette, therefore, would consist of the 16 million colors, but the program's palette would contain only the 256-color subset.

Color Space
The range of colors that can be reproduced on a computer monitor or in print form. The most commonly used color spaces for digital imaging are the baseline sRGB and wider-gamut Adobe RGB (1998).

Composition
The pleasing arrangement of the elements within a scene-the main subject, the foreground and background, and supporting subjects.


Compression
A method of reducing the size of a digital image file in order to free up the storage capacity of memory cards and hard-drives . Compression techniques are distinguished from each other by whether they remove detail and color from the image. Lossless techniques compress image data without removing detail, while "lossy" techniques compress images by removing some detail.
Joint Photographic Experts Group (JPEG) is a lossy compression technique supported by JPEG, PDF, and PostScript language file formats.


Color Temperature
A linear scale for measuring the color of ambient light with warm (yellow) light measured in lower numbers and cool (blue) light measured in higher numbers. Measured in terms of 'degrees Kelvin', daylight (mid-day) is approximately 5600-degrees Kelvin, a candle is approximately 800-degrees, an incandescent lamp is approximately 2800-degrees, a photoflood lamp is 3200 - 3400-degrees, and a mid-day blue sky is approximately 60,000-degrees Kelvin.

CompactFlash™ – A common type of digital camera memory card, about the size of a matchbook. There are two types of cards, Type I and Type II. They vary only in their thickness, with Type I being slightly thinner. A CompactFlash memory card can contain either flash memory or a miniature hard drive. The flash memory type is more prevalent.

Condenser.

Generally a simple lens used to collect light and concentrate it on a particular area, as in enlarger or projector. Frequently in the form of two planoconvex lenses in a metal housing. A condenser, normally of the fresnel type, is used to ensure even illumination of the viewing screens on SLR cameras.

Condenser Enlarger
An enlarger with a sharp, undiffused light that produces high contrast and high definition in a print. Scratches and blemishes in the negative are emphasized.

Contact Print
A print made by exposing photographic paper while it is held tightly against the negative. Images in the print will be the same size as those in the negative.

Continuous Servo AF Focus
Autofocus term used by Nikon, the AF sensor detection continues as long as shutter release button is lightly pressed and the reflex mirror is in the viewing position. Useful when the camera-to-subject distance is likely to change.

Contrast – The difference between the darkest and lightest areas in a photo. The greater the difference, the higher the contrast.

Cropping
Printing only part of the image that is in the negative or slide, usually for a more pleasing composition, in medium format, esp the 6 x 6, some form of cropping is necessary for publishing on A4 magazine format. May also refer to the framing of the scene in the viewfinder

.Curvature of Field. This optical defect causes points on an object plane perpendicular to the lens axis to focus on a curved surface rather than a plane.



D

Dark Current
Pixels collect signal-charges in the absence of light over time, which can vary from pixel to pixel. The result is known as dark current, or more commonly as noise.

Darkroom
A light tight area used for processing films and for printing and processing papers; also for loading and unloading film holders and some cameras. For image purist, the cycle of photograph is not complete if the darkroom process is not handled personally.

Data Disk
A circular, rotating disk at the end of Advanced Photo System film cassettes that functions as a circular bar code, communicating the film speed, type and exposure length through a sequence of reflective bars to an optical sensor in the camera.

Dedicated Flash
A fully automatic flash that works only with specific cameras. Dedicated flash units automatically set the proper flash sync speed and lens aperture, and electronic sensors within the camera automatically control exposure by regulating the amount of light from the flash. A simple glance can differentiate by identifying the multiple contacts on the hot shoe (the place where the flash is mounted).

Definition
The clarity of detail in a photograph.

Delayed action.
Mechanism delaying the opening of the shutter for some seconds after the release has been operated. Also known as self-timer.

Densitometer
An instrument used for measuring the optical density of an area in a negative or print.

Density
The blackness of an area in a negative or print that determines the amount of light that will pass through it or reflect from it. Sometimes referred to as contrast.

Depth of Field
The zone of acceptable sharpness in front of and behind the subject on which the lens is focused; extends approx. one-third in front of and two thirds behind the in-focus subject; dependent on three factors: aperture, focal length, and focused distance; the wider the aperture, the longer the focal length, and the closer the focused distance, the less the depth of field, and vice versa; in comparison to a normal lens, wideangle lenses have inherently more depth of field at each f-number and telephoto lenses have less.
Since this element is very important, another simpler way to explain is the amount of distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject or can explain as in simpler term as the zone of sharpest focus in front of, behind, and around the subject on which the lens is focused; can be previewed in the camera - very handy for critical work.

Depth of Focus
The distance range over which the film could be shifted at the film plane inside the camera and still have the subject appear in sharp focus; often misused to mean depth of field.

Diffuse Lighting
Lighting that is low or moderate in contrast, such as on an overcast day.

Diffusing
Softening detail in a print with a diffusion disk or other material that scatters light.

Digital Zoom
Unlike an optical zoom, the digital zoom takes the central portion of a digital image and crops into it to achieve the effect of a zoom. This means that the existing data is not enhanced or added to, merely displayed at a lower resolution, thereby giving an illusion of an enlarged image.

DIN
Deutche Industrie Norm (Film speed rating defined by the Deutscher Normenausschuss (German standards organisation).). Numeric rating used to describe emulsion speed for German Made photosensitive materials. Just as the same as ASA and ISO numbers.

Dispersion
The property of materials which have a refractive index that varies according to the wavelength of light, i.e., bend the rays of some colors more than others; a prism placed in the path of a ray of white light bends the blue and violet rays more than the orange and red, so that it spreads out or "disperses" the colors as a continuous spectrum.

Distortion
Even if the other possible aberrations were totally eliminated, images could result that still have a distorted appearance. For an example, an rectangle may appear as a barrel or pin cushion-shaped object. A lens aberration which does not affect the sharpness of the image, but alters the shape of objects; the inability of a lens to render straight lines perfectly straight; does not improve by stopping down the lens; there are two types of distortion:
Barrel: Straight lines are bowed in at the edges of the picture frame re sembling the sides of a barrel; pres ent in small amounts in some wideangle or wideangle-zoom lenses, bu~ uncorrected in fisheye lenses.
Pincushion: The opposite of barrel distortion; straight lines are bowed in toward the middle to resemble the sides of a pincushion; present in smal amounts in some telephoto and telephoto-zoom lenses.


Disk Drive
A device that both reads data from a disk and writes data onto a disk. A disk drive spins the disk at high RPMs while one or more heads that read and write data. There are different types of disk drives for different types of disks. For example, a hard disk drive (HDD) reads and writes hard disks, and a floppy drive (FDD) accesses floppy disks. A magnetic disk drive reads magnetic disks, and an optical drive reads optical disks. Disk drives can be either internal (housed within the computer) or external (housed in a separate box that connects to the computer).

DSLR (Digital Single Lens Reflex)
A digital single lens reflex camera.

Dodging – Selectively lightening part of a photo with an image editing program.

Double Exposure
Two pictures taken on one frame of film, or two images printed on one piece of photographic paper. Some cameras can have double exposure level depressed with multiple exposures one even with a motor drive.


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.

Driver
A program that controls the sequencing of commands for an input/output device. Every device, whether it is a printer, disk drive, or keyboard, must have a driver program. A driver acts like a translator between the device and programs that use the device. Each device has its own set of specialized commands that only its driver knows.

Dye-Sublimation
A printing method where a waxy ink is heated to temperatures high enough for the ink to vaporize, and is then forced to bond with a special receiver paper. The dye sublimation (dye-sub) printing method produces images with continuous tone color.

Dynamic Range
The range of brightness and tonality reproduced in a digital (or traditional) photographic image. Wider dynamic range translates into greater tonal values between the darkest shadow details and the brightest highlight details.

E

Effective Pixels
The effective pixels of a sensor are a measurement of the number of pixels of a sensor that actually record the photographic image. As an example a camera might contain a sensor that contains 10.5 megapixels, but an effective pixel count of 10.2 megapixels. The reason for this discrepancy is because digital imaging sensors have to dedicate a certain percentage of available pixels to establish a black reference point. These pixels are usually arranged frame-like along the edge of the sensor, out of range of the recorded image.

EV
Exposure value. Method of quantifying scene brightness. Most of these value apply to metering cells, how high or low eg. a metering that can handles from EV1-EV21 means a metering system that can measure brightness level from just above the light level of a candle light to a brightly sunlight scene on a beach. Camera metering can handle more weakly on a spot meter than, say, a center weighted average metering system. EV is commonly used in black & White photographic process. At ISO 100, the combination of a one-second shutter speed and an aperture of F1.4 is defined as EV1. The camera may be used only within the EV range of the exposure meter. For example, the exposure metering range s from EV0 to EV20 can be used on a camera, means the camera's meter can handle broader range of exposure latitude.

Existing Light
Available light. Strictly speaking, existing light covers all natural lighting from moonlight to sunshine. For photographic purposes, existing light is the light that is already on the scene or project and includes room lamps, fluorescent lamps, spotlights, neon signs, candles, daylight through windows, outdoor scenes at twilight or in moonlight, and scenes artificially illuminated after dark.




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.

Export
The act of sending a file out through a specialized mini-application or plug-in so as to print or compress it. The term is also used to describe the action of saving the data to a specialized file format, i.e. JPEG, or GIF.

Exposure
Exposure explains how light acts on a photographic material. The lens opening (f-stop or aperture) controls light intensity, while the duration is controlled by the shutter speed. A camera with auto-exposure can automatically control the exposure. The same principle works with digital cameras where film is replaced by the CCD.

Exposure Compensation
Adding to or subtracting from the 'correct' exposure time indicated by the camera's meter, which results in a final exposure that is either lighter or darker than the recommended exposure time. Most cameras allow for exposure compensation in ½, 1/3, or full-stop increments.


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. Many fun and creative effects can be created with external flash.



F

F-stop
A term used to describe the aperture, or opening of a lens. F-stops are defined numerically - f1/4, f5.6, f22, etc. Larger, or wider apertures, allow more light to enter the lens, which results in faster shutter speeds. Faster apertures also allow for selective focus (narrow depth-of-field), while smaller (slower) apertures allow for greater depth-of-field. Wider apertures are preferred for portraits, while smaller apertures are preferred for landscapes.

File format
The way an image is saved to a digital camera's memory. The JPEG format is the most common file format found in digital cameras. Other commonly used formats include Tiff, RAW, PSD, and Bitmap

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.

Filter
A colored piece of glass or other transparent material used over the lens to emphasize, eliminate, or change the color or density (ND) of the entire scene or certain areas within a scene. Also see "colour temperature", "UV". Technically, it explained as a piece of material which restricts the transmission of radiation. Generally coloured to absorb light of certain colours. Can be used over light sources or over the camera lens. Camera lens filters are usually glass either dyed or sandwiching a piece of gelatin in a screw-in filter holder.

Finder
Also known as viewfinder and projected frame. A viewing device on a camera to show the subject area that will be recorded on the film.

Fisheye lens.
Ultra-wide angle lens giving 180 angle of view. Basically produces a circular image on 35 mm, 5-9 mm lenses showing whole image, 15-17 mm lenses giving a rectangular image fitting just inside the circle, thus representing 180 across the diagonal.

Fixed-Focus
Describes a non-adjustable camera lens, set for a fixed subject distance.

Fixed-Focus Lens
A lens that has been focused in a fixed position by the manufacturer. The user does not have to adjust the focus of this lens, applies on most entry or disposable cameras.


FireWire – A type of cabling technology for transferring data to and from digital devices at high speed. Some professional digital cameras and memory card readers connect to the computer over FireWire. FireWire card readers are typically faster than those that connect via USB. Also known as IEEE 1394, FireWire was invented by Apple Computer but is now commonly used with Windows-based PCs as well.

Flash Exposure Bracketing:
Enables a photographer to automatically bracket exposures at varied flash output levels, in TTL auto flash shooting, without changing the shutter speed and/or aperture, this is a one of the top flash feature that can only be found on some higher ranked cameras.

Flash Sync
Flash sync is used to describe either the connection point where you plug an external electronic flash into your camera (usually a PC port or the camera's hot-shoe), or the fastest shutter speed your camera can 'sync' with an external flash. Most DSLRs have top sync speeds of 1/125 th to 1/250 th, though some camera/flash combinations can be synced at speeds of up to 1/15,000 th.

Flash sync speed :
Exposure time with a focal-plane shutter is measured from the instant the first curtain is released, to begin its travel across the frame, until the instant the second curtain is released, to begin its travel across the frame. When the first curtain reaches the end of its travel, the film frame is uncovered as far as the first curtain is concerned, so it closes the electrical contacts for X sync and fires the flash instantly. Shutter speed at which the entire f iIm frame is exposed when the flash s fired in flash shooting. Most modern camera with vertical travel shutter curtain have faster flash sync speed like 1/250 sec. or slower, some top camera model like Nikon F5, changeable to 1/300 sec. with the Custom Setting.

Flat Lighting
Lighting that produces very little contrast or modeling on the subject plus a minimum of shadows.

Focal Length Magnifier
Also known as Magnification Factor, this term is used to describe the angle of view of a lens used on a DSLR in terms of how it would appear on a full-frame 35mm camera. Nikon, Pentax, Fuji , and Sony (Alpha A100) DSLRs contain APS-C sized sensors that are 50% smaller (1.5x) than a standard 35mm frame. As a result, the effective focal length of a 50mm lens on any of theses DSLRs would be 'cropped' to 75mm. Canon EOS Rebels and the Canon EOS 30D have a 1.6x magnification factor which would make a 50mm lens effectively an 80mm lens, while on a Canon EOS 1D Mark II (1.3x) a 50mm would effectively be the equivalent of a 65mm lens.

f-Number
A number that indicates the size of the lens opening on an adjustable camera. The common f-numbers are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22. The larger the f-number, the smaller the lens opening. In this series, f/1.4 is the largest lens opening and f/22 is the smallest. Also called f-stops, they work in conjunction with shutter speeds to indicate exposure settings. Also can be explained as numerical expression of the relative aperture of a lens at its different stops; equal to the focal length divided by the effective aperture of the lens opening and written in various forms, such as f/8, f8, 1: 8, etc.; each f-number is 1.4 times larger than the preceding one; each number indicates a halving or doubling of the amount of light allowed to pass through the lens; the next higher numbered f-number sign)fies an aperture which lets in exactly onehalf as much light, and the next lower number, twice as much light, i.e., f/11 lets in half as much light as f/8, while f/5.6 lets in twice as much; all lenses stopped down to the same f-number produce images of equal illumination (apart from differences due to varying reflection losses); therefore, for a given shutter speed, a given fnumber always corresponds to the same exposure.

f/stop
A fraction which indicates the actual diameter of the aperture: the "f" represents the lens focal length, the slash means "divided by," and the word "stop" is a particular f-number; for example, with a 50mm f/1.4 lens, the actual diameter of its maximum aperture is 50mm divided by 1.4 or 35.7mm; at f/2, the diameter becomes 50mm/2 or 25mm; at f/2.8, the aperture is 50mm/2.8 or 17.9mm across; as the numerical value of the f/stop increases, the aperture decreases in size.

Focal Length
The distance between the film and the optical center of the lens when the lens is focused on infinity. The focal length of the lens on most adjustable cameras is marked in millimetres on the lens mount. The distance from the principal point to the focal point. In 35mm-format cameras, lenses with a focal length of approx. 50mm are called normal or standard lenses. Lenses with a focal length less than approx. 35mm are called wide angle lenses, and lenses with a focal length more than approx. 85mm are called telephoto lenses. Lenses which allow the user to continuously vary the focal length without changing focus are called zoom lenses .
FP (Focal Plane) flash Bulb

A special flashbulb that can be used at certain shutter speeds is called "FP" where the initials stand for Focal Plane. Designed for use with focal-plane shutters these bulbs make a nearly uniform amount of light for a relatively long time. Generally, FP flashbulbs can be used with any shutter speed and any firing delay except "X sync". The FP bulb will extinguish during exposure intervals longer than 1/60 second but enough light will have reached the film to make the exposure.

Focal-Plane Shutter
An opaque curtain containing a slit that moves directly across in front of the film in a camera and allows image-forming light to strike the film.

Focus
Adjustment of the distance setting on a lens to define the subject sharply. Generally, the act of adjusting a lens to produce a sharp image. In a camera, this is effected by moving the lens bodily towards or away from the film or by moving the front part of the lens towards or away from the rear part, thus altering its focal length.

Focus Range
The range within which a camera is able to focus on the selected picture subject - 4 feet to infinity - for example.

Focus-Priority for autofocus :
Shutter cannot be released until the subject s in focus. For situations when an in-focus subject s important. With the F5 camera body, Focus-Priority s given to Single Servo AF mode while Release-Priority is g iven to Continuous Servo AF. Using Custom Setti ing, however, you can change the priority to Release-Priority Single Servo AF or Focus-Priority Continuous Servo AF.

Focus Tracking :
Enables the camera to analyze the speed of the movi ing subject according to the focus data detected, and to obtain correct focus by anticipating the subject's position and driving the lens to that position&emdash;at the exact moment of exposure, basically a Nikon's and Canon's feature. Currently, Nikon lead the pack in this tecnology with the F5, the fastest among all.

Fogging
Darkening or discoloring of a negative or print or lightening or discoloring of a slide caused by exposure to nonimage-forming light to which the photographic material is sensitive, too much handling in air during development, over-development, outdated film or paper, or storage of film or paper in a hot, humid place.

Format
The actual size of the photograph, either slide or negative, produced by a camera; in 35mm photography, the picture measures 24mm x 36mm and has a diagonal of 43mm, While the new APS (Advance Photo System), several new formats were included, including panorama . While it can also be explained as shape and size of image provided by camera or presented in final print or transparency. Governed in the camera by the opening at the rear of the body over which the film passes or is placed. The standard 35 mm format is 36 x 24 mm; half-frame, 18 x 24 mm; 126 size, 28 x 28 mm; 110, 17 x 13 mm; standard roll film (120 size), 2x 2 in.

Foreground
The area between the camera and the principal subject.

Front-Curtain Sync :
The flash fires an instant after the front curtain of a focal plane shutter has completed its travel across the film plane. This is the way the camera operates with the flash sync mode at Normal Sync. (See "Rear-Curtain Sync".)

Fresnel. Pattern of a special form of condenser lens consisting of a series of concentric stepped rings, each ring a section of a convex surface which would, if continued, form a much thicker lens. Used on focusing screens to distribute image brightness evenly over the screen.

Fringing
Fringing, commonly associated with less-expensive lenses, describes the 'bleeding' of color along the edges of contrasty portions of a digital image. Fringing often shows up as cyan blurring on one side of a contrasty object complimented by red or magenta blurring on the opposite side of the object.


G

Gamma
The brightness curve of the color spectrum as displayed (or reproduced) on a computer monitor, a printer, or scanner.

Gain
Gain refers to the relationship between the input signal and the output signal of any electronic system. Higher levels of gain amplify the signal, resulting in greater levels of brightness and contrast. Lower levels of gain will darken the image, and soften the contrast. Effectively, gain adjustment affects the sensitivity to light of the CCD or CMOS sensor. In a digital camera, this concept is analogous to the ISO or ASA ratings of silver halide films.

GIF
Graphic Interface designed by CompuServe for using images online. This is a 256-color or 8 bit image.
Gigabyte
One gigabyte is equal to 1,024 megabytes. Gigabyte is often abbreviated as G or GB.

Grain. Minute metallic silver deposit, forming in quantity the photographic image. The individual grain is never visible, even in an enlargement, but the random nature of their distribution in the emulsion causes over-lapping, or clumping, which can lead to graininess in the final image. Also cross check with below for graininess.

Graininess
The sand-like or granular appearance of a negative, print, or slide. Graininess becomes more pronounced with faster film and the degree of enlargement.


Grayscale – A photo made up of varying tones of black and white. Grayscale is synonymous with black and white.

GUI ( Graphic User Interface )
Pronounced "Gooey." Refers to a program interface that takes advantage of the computer's graphics capabilities to make the program easier to use.


H

Handle Mount flash
Also often referred as bracket flash. It comprised of one arm of the L-shaped bracket extends under the camera body and uses the camera's tripod socket to mount the camera on the bracket. The vertical arm of the bracket serves as a handle and mounts a flash unit in an accessory shoe often on top of the handle portion, but there are other methods. Flash mounted in a bracket usually requires a separate electrical cord to make the electrical connection between camera body and flash unit.

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.

Hot Shoe
A 'live' accessory shoe, usually located on the top of the camera prism housing that enables you to mount and trigger an electronic flash or wireless transmitter.

Hot Swap
The ability to add or remove peripheral devices (scanners, disk drives, etc.) to a computer without having to re-boot the system. USB and FireWire interfaces are 'hot-swappable' interfaces.

Hyperfocal Distance
Distance of the nearest object in a scene that is acceptably sharp when the lens is focused on infinity.


I

ICC Profile (International Color Consortium profile)
A universally recognized color management standard for specifying the color attributes of digital imaging devices (scanners, digital cameras, monitors and printers) in order to maintain accurate color consistency of an image from the point of capture through the output stage.

IEEE-1394 interface (FireWire)
A very fast external bus standard that supports data transfer rates of up to 400 Mbps (400 million bits per second). Products supporting the 1394 standard go under different names, depending on the company. Apple, which originally developed the technology, uses the trademarked name FireWire. Other companies use other names, such as i.link and Lynx, to describe their 1394 products. In addition to its high speed, 1394 also supports isochronous data -- delivering data at a guaranteed rate. This makes it ideal for devices that need to transfer high levels of data in real-time, such as video devices.

Image Editing Software
Software that allows you to electronically retouch digital image files including the ability to adjust the color, contrast, sharpness, size, and other tonal characteristics of the file.


Image resolution - The number of pixels in a digital photo is commonly referred to as its image resolution.

Image Stabilization (IS) or Vibration Reduction (VR), anti-shake technology is a method of reducing the effects of camera movement to the photographic image. Image stabilization can be achieved in the lens or in the camera body. In-camera Image Stabilization is achieved by mounting the camera sensor on a 'floating' micro-geared stage that rapidly shifts the sensor in the opposite direction of the camera's movement, which effectively cancels out the image movement.
The alternative method of canceling camera movement is by employing a gyroscopically-driven 'floating' element in the rear portion of the lens that rapidly shifts the element in the opposite direction of the camera movement. Needless to say, either process is quite complex and requires extreme high-speed data processing coupled with precision lens/sensor movements in order to achieve the desired effect.
The ultimate benefit of IS technology is that it enables you to hand-hold a camera three to four shutter-speeds slower than non-IS enabled cameras or lenses.

Inkjet – A printer that places ink on the paper by spraying droplets through tiny nozzles.

Incident light.
Light falling on a surface as opposed to the light reflected by it.

Infinity.
Infinite distance. In practice, a distance so great that any object at that distance will be reproduced sharply if the lens is set at its infinity position, i.e. one focal length from the film.

Interspersed Aspect Ratio
A basic requirement of certified photofinishers and certified photofinishing equipment; specifies the three system print formats - C, H and P - that users select during picture-taking must be available at photofinishing.

Interchangeable lens.
Lens designed to be readily attached to and detached from a camera.

Inverted telephoto lens.
Lens constructed so that the back focus (distance from rear of lens to film) is greater than the focal length of the lens. This construction allows room for mirror movement when short focus lenses are fitted to SLR cameras.

Iris.
Strictly, iris diaphragm. Device consisting of thin overlapping metal leaves pivoting outwards to form a circular opening of variable size to control light transmission through a lens.

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.


J

Jaggies
Term for the stair-stepped appearance of curved or angled lines in a digital image file. The smaller the pixels and/or the greater their number, the less apparent the "jaggies".


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.

L

LAB Color
A perceptually linear color space (RGB and CMYK are non-linear color spaces) that utilizes luminance as a means of increasing contrast and color saturation.

Lag Time
Also known as shutter lag, lag time refers to the delay that sometimes occurs between the time the shutter button is pressed and the time the shutter actually fires. Shutter lag is most prevalent when using less expensive point-and-shoot cameras.

LCD ( Liquid Crystal Display )
LCD screens, usually found on the rear of digital cameras, allow you to preview and/or review photographs you have taken. LCDs utilize two sheets of polarizing material with a liquid crystal solution between them. An electric current passed through the liquid causes the crystals to align so light cannot pass through them. Each crystal, therefore, is like a shutter, either allowing light to pass through or blocking the light.

Lithium-Ion
A type of rechargeable battery that was originally developed for use with camcorders, and is now used as a power source for many digital still cameras

Lossy
A data compression technique that can reduce the detail of a digital image file. Most video compression techniques utilize lossy compression.

Low-Pass Filter
Used with digital imaging, low-pass filters are integrated into many digital sensors to suppress color ghosting and the effects of infra-red light.



M

Macro Lens
A lens that provides continuous focusing from infinity to extreme close-ups, often to a reproduction ratio of 1:2 (half life-size) or 1:1 (life-size).

Manual flash :
Flash output is controlled manually in manual flash mode unlike in auto flash mode, where flash output power varies automatically according to the selected aperture. Some Speedlights, example like the Nikon SB 27, SB 26, SB-25. SB-24 and SB 20, provide selectable manual outputs (full, 1/2, l/4, 1/8, l/16 etc.), while others provide full manual output only.

Matrix Metering
Also known as Segmented Metering, Matrix metering takes the total image area and breaks it into sections, which are analyzed by the camera's light meter and compared to the light values of the surrounding sections. The results are then compared to similar lighting situations stored in the camera's memory, and a correct exposure is established. This entire process occurs in a few microseconds.


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 memory card slightly smaller than a single stick of chewing gum. Like CompactFlash and SmartMedia, it is flash-based storage for your photos.

Microlenses
Microlenses are commonly mounted onto the tops of the light-gathering portion of pixels (a.k.a. photon). Microlenses capture the light striking the top portion of the camera sensor's pixels and redirect it into the pixel for processing. Microlenses are often angled along the edges of camera sensors in order to capture and redirect light back into the pixel as a method of reducing light falloff on the edges of the image.

Mirror lens (Reflex Lens).
Lens in which some (usually two) of the elements are curved mirrors. This construction produces comparatively lightweight short fat long focus lenses. They cannot be fitted with a normal diaphragm.

Modelling.
Representation by lighting of the three-dimensional nature of an original in a two-dimensional reproduction.

Monitor Pre-flash(es):
When performing Automatic Balanced Fill-Flash with TTL Multi Sensor, the Speedlight fires a series of scarcely visible pre-flashes to enable the camera's computer to pre-analyze the scene. The TTL Multi Sensor ins de the camera body reads the amount of reflected light, then the camera's microcomputer determines the area of the TTL sensor to be used for flash output control and adjusts the flash output level. The Monitor Pre-flashes are visible but not recognizable.

Moiré
Patterns formed in portions of a photographic image as a result of confusion between a pattern within the photographic scene and the pattern of pixels within the sensor. Moiré can often be eliminated, or greatly reduced, by moving either closer to or further from your subject. Higher-resolution imaging sensors tend to be less prone to moiré problems.


N

ND
Neutral Density. Usually applies on filter, filtration that can effectively reduce the amount of light passes to the film. In some filters, half ND filters can be very effective to lower the contrast, esp the sky to achieve more balance effect. Lens like reflex lenses, where its aperture is fixed, ND filter can be the only way to play around with exposures. Certain 617 format is providing with a central ND filter.

NiCD ( Nickel-Cadmium )
A type of rechargeable battery. The NiCD battery was one of the first successful rechargeable batteries used in small electronics such as digital cameras.

NiMH ( Nickel-Metal Hydride )
A commonly used rechargeable battery for digital cameras and camcorders.

Noise
A common bugaboo of JPEG files, noise is the appearance of color artifacts within a digital image. Mostly noticeable in the shadow areas of images captured at higher ISO ratings, the image processors used in many current digital cameras utilize noise-suppression software to minimize the appearance of noise artifacts. Heat build-up due to continuous shooting in hot environments can also cause noise artifacts within digital images.

Noise Reduction
A process within a digital camera's image processor in which the artifacts caused by 'pushed' ISO ratings and/or other electrical or heat-related artifacts are suppressed or eliminated in an image

Non-lossy (a.k.a. lossless)
A term that refers to data compression techniques that do not remove image data details in order to achieve compression. This method is generally less effective than lossy methods in terms of resulting file size, but retains the entire original image. See also lossy.

Non-Volatile Memory
A type of memory card that retains data when power is turned off. Camera Memory Cards (Compact Flash, SmartMedia, etc.) use non-volatile memory.

NTSC
National Television Standards Committee. Standards for video broadcasting and recording in the US and Japan. PAL's the standard in Great Britain and the commonwealth countries. SECAM used in many countries in the European communities


O

Operating System
Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

Optical Resolution
The physical resolution at which a device can capture an image. The term is used most frequently in reference to optical scanners and digital cameras.

Optical Zoom
An optical zoom is made to bring you closer to your subject, without you having to move. Zooms are constructed to allow a continuously variable focal length, without disturbing focus.

Overexposure
A condition in which too much light reaches the film, producing a dense negative or a very bright/light print or slide.



P

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.

Panorama
A broad view, usually scenic.

Parallax
With a lens-shutter camera, parallax is the difference between what the viewfinder sees and what the camera records, especially at close distances. This is caused by the separation between the viewfinder and the picture-taking lens. There is no parallax with single-lens-reflex cameras because when you look through the viewfinder, you are viewing the subject through the picture-taking lens.

Perspective
The rendition of apparent space in a flat photograph, i.e., how far the foreground and background appear to be separated from each other; determined by only one factor: the camera-to-subject distance; if objects appear in their normal size relations, the perspective is considered "normal"; if the foreground objects are much larger than the ones in the background, the perspective is considered "exaggerated"; when there is little difference in size between foreground and background, we say the perspective looks "compressed."

Photo File Index Print
A basic system feature that makes ordering reprints and enlargements easy; the small print shows a positive, "thumbnail"-sized version of every picture on an Advanced Photo System film roll; accompanies all prints and negatives returned in the sealed film cassette by the photofinisher; each thumbnail picture is numbered on the index print to match negative frames inside the cassette.

PhotoShop Plug-in
A software application that allows a camera, scanner or printer to work directly with Adobe PhotoShop software.

PICT
The PICT format was originally developed by Apple Computer in the mid-1980s. The PICT format supports RGB files with a single alpha channel, and indexed-color, grayscale, and Bitmap files without alpha channels. The PICT format is especially effective at compressing images with large areas of solid color.

Pixel
Short for picture element, Pixels are the tiny components that, working together, capture the digital image record in your camera, and later view on a computer monitor. The more pixels that there are, the higher the screen or image resolution will be.

Pixelization
The ‘break-up’ of a digital image file that has been scaled up (enlarged) to a point where the pixels no longer blend together to form a smooth image.
Pixelization can also appear in the form of step-like, or choppy curves and angled lines (also known as the 'jaggies'. As a rule the greater the number of pixels within an image, the less likely you will see pixelization within an image.

Pincushion Distortion
An optical distortion, common in less expensive lenses, where parallel lines on the horizontal and/or vertical plane bow inward. Pincushion distortion is the opposite of barrel distortion.

Plug-and-Play
Refers to the ability of a computer system to automatically configure expansion boards and other devices without having to restart the CPU or reset DIP switches, jumpers, and other configuration elements.

PNG ( Portable Network Graphics )
Developed as a patent-free alternative to GIF, this format is used for lossless compression for the purposes of displaying images on the World Wide Web. Adopted by the WWW consortium as a replacement for GIF, some older versions of Web browsers may not support PNG images.

Polarising Screen (Filter)
A filter that transmits light travelling in one plane while absorbing light travelling in other planes. When placed on a camera lens or on light sources, it can eliminate undesirable reflections from a subject such as water, glass, or other objects with shiny surfaces. This filter also darkens blue sky.

Polarized light.
Light waves vibrating in one plane only as opposed to the multi-directional vibrations of normal rays. Natural effect produced by some reflecting surfaces, such as glass, water, polished wood, etc., but can also be simulated by placing a special screen in front of the light source. The transmission of polarized light is restrained by using a screen at an angle to the plane of polarization.

Port
An interface on a computer to which you can connect a device. Most personal computers have USB, USB 2.0, and/or FireWire ports.

PPI (Pixels-Per-Inch)
Also referred to as DPI (Dots per Inch), the higher the PPI, the higher the image quality of the final print

Processing
Developing, fixing, and washing exposed photographic film or paper to produce either a negative image or a positive image.

Program Exposure
An exposure mode on an automatic or autofocus camera that automatically sets both the aperture and the shutter speed for proper exposure.

Programmed Auto:
Camera sets both shutter speed and aperture for correct exposure





R

RAM
Random Access Memory. A type of computer memory that can be accessed randomly. Most computers allow for installing additional RAM, which increases the computer’s ability to process data faster.

Rangefinder
Instrument for measuring distances from a given point, usually based on slightly separated views of the scene provided by mirrors or prisms. May be built into non-reflex cameras. Single-lens reflexes may have prismatic rangefinders built into their focusing screens. The Leica and the Contax G2 still keep the flag up in this areas.

RAW Files
Many pro and semi-pro digital cameras have the option of capturing RAW files, which unlike JPEGs, TIFFs, and other file formats contain all of the data captured during the exposure in an un-edited format. When processed, RAW files can be adjusted far more extensively than images captured in other imaging formats, and can be saved as JPEGs, TIFFs, etc. The original RAW file remains unaltered and can be reprocessed at any time for other purposes.

Rear-Curtain Sync:
Flash fires an instant before the second (rear) curtain of the focal plane shutter begins to move. When slow shutter speeds are used, this feature can create a blur effect from the ambient light, i.e., a flowing- light patterns following a moving subject with subject movement frozen at the end of the light flow. (See "Front-Curtain Sync".) Most mid range and top flight auto camera models have this feature.

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.

Red-eye Reduction
A method of reducing or eliminating red-eye from flash photographs by using a short burst of light, or pre-flash, to momentarily ‘stop-down’ the pupils of the subject’s eyes prior to the actual flash exposure. Red-eye can also be eliminated electronically after-the-fact in many photo-editing programs. Many digicams contain software applications that electronically eliminate red-eye in-camera.

Reflector
Any device used to reflect light onto a subject to improve balance of exposure (contrast). Another way is to use fill in flash.

Reflex
A reflex camera is one that utilizes a mirror system to reflect the light (the image) coming through the lens, to a visible screen. The image seen in the camera's viewfinder is the same image that strikes the camera's imaging sensor (or filmplane). This system provides the most accurate framing and focusing. The reflex system avoids the parallax problem that plagues most direct view cameras. Reflex cameras are also called SLRs, or DSLRs.

Release-Priority :
For autofocus, shutter can be released anytime (i.e., even when subject is not in focus). Helps you avoid missed opportunities when you are not concerned with absolute focusing precision, terms apply primarily for Nikon.

Remote Capture
The ability to trip the camera shutter from a distance using a cable release or wireless device.

Resolution
Refers to the number of pixels, both horizontally and vertically, used to either capture an image or display it. The higher the resolution, the finer the image details.

Retouching
Altering a print or negative after development by use of dyes or pencils to alter tones of highlights, shadows, and other details, or to remove blemishes.

RGB Color ( Red Green Blue)
Computers and other digital devices handle color information as shades of red, green and blue. A 24-bit digital camera, for example, will have 8 bits per channel in red green and blue, resulting in 256 shades of color per channel.



S

Saturation – How rich the colors are in a photo.

Selective Focus
Choosing a lens opening that produces a shallow depth of field. Usually this is used to isolate a subject by causing most other elements in the scene to be blurred

Sensitivity – See ISO speed.

Serial – A method for connecting an external device such as a printer, scanner, or camera, to a computer. It has been all but replaced by USB and FireWire in modern computers.

SD Card (Secure Digital)
Far smaller than CompactFlash cards (CF), Secure Digital memory cards have enabled camera manufacturers to further reduce the size of digicams. They are also commonly found in cell phones, PDAs, and other small electronic devices that incorporate removable memory.

Sharpness – The clarity of detail in a photo.

Shutter
A mechanism in the camera that controls how much light reaches the film.

Shutter Priority
A metering mode in which the shutter-speed is fixed and the exposure is controlled by opening or closing the lens aperture. Most modern cameras have step-less shutters that can be triggered to open and close infinitely between the camera's fastest and slowest shutter speeds, i.e. 1/236 th, 1/54 th, 1/5829 th, etc..

Shutter speed
The length of time the shutter remains open when the shutter release is activated, expressed in fractions or multiples of a second.

Sidelighting
Light striking the subject from the side relative to the position of the camera; produces shadows and highlights to create modelling on the subject.


SLR (Single-Lens-Reflex)
A camera that utilizes a prism and mirror system to project the image seen by the lens onto a focusing screen located below the prism housing. The image the user sees in the viewfinder is identical to the image being recorded.

Slave Unit
Accessory flash "slave" units are available to fire multiple flash units without multiple electrical connections to the camera. These units sense the light output of the first flash, which is mounted in the camera hot shoe, or cord-connected to the camera. When the light output is sensed, the slave unit triggers a second flash unit that is connected only to the slave. Additional slaves and flash units can be used, if needed.

Slow Sync
A flash technique for using the flash at a slow shutter speed. Flash shooting in dim light or at night at a fast shutter speed often results in a flash-illuminated subject against a dark background. Using a slower shutter speed with the flash brings out the background details in the picture. Use of a slow shutter speed with Rear-Curtain Sync is particularly effective for illustrating the movement of a stream of light. Can be of very creative if put to good use.

Soft Focus
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