Article: DLSR Glossary

100 Percent Crop: A section of an image that hasn't been reduced in size, which allows others to see the quality of an image at full size without having to display or send a full image.

35mm Equivalency: What a lens on a smaller DSLR sensor would be equivalent to in terms of a 35mm film SLR camera – see Focal Length Multiplier.

67/645: Older Pentax lens mount.

AA Filter: Anti-Aliasing Filter – see Low Pass Filter.

Adobe Photoshop: One of the most common, and probably most powerful image editing applications.

AE Lock: Half pressing the shutter release usually causes the camera to focus and set exposure. Depending on how the camera is configured, pressing the AE Lock button will lock the exposure and prevent it from changing while you recompose the picture.

AF-S: A designation found on some Nikon lenses, that indicates they use an in-lens focusing motor. See Silent Wave Motor for more information.

Angle of View: The angle of view is determined by the focal length of the lens and the size of the image sensor. The longer the focal length of the lens, the narrower the angle of view.

Anti-Aliasing: Anti-Aliasing is the process of reducing the 'stepping' effect by smoothing diagonal lines and curves in digital images. Performed by Image Editing Software.

Aperture: A diaphragm inside the lens itself that controls the amount of light entering the camera. The aperture is measured in f-stops.

Aperture Priority AE: Aperture Priority Auto Exposure allows the user to select the aperture, or f-stop, and the camera then selects the shutter speed automatically based on lighting conditions. Aperture priority is commonly used for landscape and portrait photography where controlling the depth of field is more important.

Aperture Ring: Some lenses have aperture rings on the lens body, allowing the user to manually control the aperture.

APS-C (Advanced Photo System – Classic): Also referred to as just APS. Originally a film format, now used by most manufacturers to refer to their non full-frame sensor sizes, which are approximately the same size as the old APS film negatives.

Archive: Generally refers to long term storage – either backing up your digital images to CD, DVD or external drive.

Artifacts: Unwanted pixels or shapes in a digital image, often a result of post-processing actions like over-sharpening or JPEG compression.

Aspect Ratio: The ratio between the lengths of the sensor sides. Most DSLR's have an aspect ratio around 3:2.

Aspherical Lens: An aspheric lens is a lens whose surfaces have a profile that is neither a portion of a sphere nor of a circular cylinder. Any camera lens that includes at least one aspheric element is often called an aspherical lens.

Auto Exposure (AE): A camera mode where the camera meters the lighting conditions and sets a combination of settings, including white balance, aperture, shutter speed etc. The three primary AE Modes are Aperture Priority, Shutter Priority and Program.

Autofocus (AF): The camera/lens will automatically focus, depending on the focus mode and focus area selected.

Automatic White Balance (AWB): A feature where the camera sets the white balance setting automatically.

Back Lit: The subject being lit from behind. This can cause underexposure of the main subject in the image unless Fill-in-Flash is used. Also used in portrait photography to highlight the hair.

Banding: The presence of unwanted stripes or bands in the image. Was an early problem with the Nikon D200, but fixed with a firmware update.

Barrel Distortion: The opposite of pincushion distortion, the image is expanded towards the center. For example, a photograph of a rectangular object would have its sides bow towards the outside of the image. Can be fixed with most image editing software. Usually more of a problem with wide-angle lenses, however fisheye lenses exhibit extreme barrel distortion by design.

Batch Processing: The process of making the same change to multiple images in one go (one batch). Many image editing software packages support batch processing – for example selecting several images and applying the same sharpening to all of them with one command.

Battery Grip: A grip available for some DSLR's that attaches to the bottom of the camera. Battery Grips increase available power by incorporating additional batteries, creates a hand grip to use the camera in portrait (vertical) orientation, and in some cases adds a shutter release and command dials in portrait mode, and may increase the frame rate of the camera.

Bayer Filter: The most common type of Color Filter Array used by modern DSLR's. The Bayer Filter sits on top of the image sensor, and controls which color light enters which photosite. A bayer filter uses alternating rows of red/green and green/blue patches.

Bit: Short for 'Binary Digit'. The smallest unit of digital data, represented by a value of '1' or '0'.

Bit Depth: The number of bits used to define color of each pixel in an image. The higher the bit depth, the more colors that can be represented.

Bitmap: An image file format, denoted by the .BMP extension.

Blooming: An unwanted halo effect that can occur at borders between dark and light tones. There is a limit to how much charge a photosite can store, and in extreme cases the charge can overflow into a neighboring photosite causing this effect.

Blown Highlights: Areas of the image that are very overexposed (received more light than the sensor could record), and are represented as pure white so all detail is lost.

BMP: The file extension used by the Bitmap image file format.

Body: The camera itself (without the lens). The body contains the sensor, batteries, processor, controls, viewfinder, LCD and the user interface etc.

Borderless: A printed photograph with no border.

Bracketing: See Exposure Bracketing.

Brightness: The value of a pixel in a digital image giving its value of lightness from black to white.

Buffer: RAM inside the camera that is used to store images while they are waiting to be written to the memory card. A camera may be able to shoot at 10 frames per second, but may only be able to write 2 or 3 frames per second to the memory card, so the images are written to the buffer so the camera can carry on shooting until the buffer is full. Once the buffer is full, the frame rate will drop to the speed of the card – another shot cannot be taken until an image in the buffer has been written to the card.

Bulb: Term used for long exposure settings (normally over 30 seconds) – the shutter is opened when the shutter release is depressed, and stays open until the shutter release is released. A remote release is recommended to avoid camera shake.

Burst Mode: See Continuous Mode.

Byte: A unit of computer memory, a collection of 8 Bits of data.

Calibration: Setting up equipment to give predictable results. To get the very best results printing photographs, it helps to have both the monitor and printer calibrated to display colors correctly.

Camera Shake: Very small movements of the camera while taking a picture that result in a blurred image. Camera shake tends to get worse with longer focal lengths and slower shutter speeds. There are several ways to counter camera shake, including using faster shutter speeds, monopods, tripods, and lenses or cameras with some kind of vibration reduction or image stabilization.

CaptureNX: Nikons powerful Image Editing Software, allowing you to make numerous changes to the image.

Card Reader: A device that attaches to a computer that lets you retrieve the contents of a memory card. Using a card ready is often a faster way to download images than connecting the camera directly to the computer.

CCD (Charge-Coupled Device) : A type of sensor (light gathering chip) used in digital cameras.

Center Weighted: An automatic exposure mode that uses the middle area of the image only to determine exposure.

Channel: One piece of information stored with an image. E.g. a 24-bit true color image has 3 channels, one each for red, green and blue.

Chimping: One of the following:

1. The act of checking every photo on the LCD of a DSLR immediately after capture.
2. Jumping up and down and pretending to be a monkey. A banana adds to the effect.

Chroma: The color of an image element (pixel). A chroma is consists of saturation and hue values, but is separate from the luminance value.

Chromatic Aberration: See also purple fringing - a purple 'rim' that sometimes appears around high contrast areas in digital images. It can usually be fixed with image editing software.

Cloning: Performed with Image Editing Software, the process of reproducing part (or all) of a digital image to transfer either to another image file, or a different area within the same image.

CMOS (Complementary Metal-Oxide Semiconductor) : A kind of digital image sensor, that uses less power than CCD sensors.

CMS (Color Management System) : Setting up hardware and software to ensure color matching and calibration between cameras and/or computer monitors, and any form of printer or other hard copy output.

CMYK: The colors used in four color printing, Cyan, Magenta, Yellow and Black.

Color Balance: Color balance refers to adjusting the relative amounts of colors in an image so that neutral colors are reproduced correctly. Also refered to as 'gray balance', 'neutral balance', or 'white balance'.

Color Cast: A color cast is a tint of a particular color (usually unwanted), which affects the entire photographic image.

Color Correction: To correct or enhance the colors in an image to give a more natural looking picture.

Color Depth: Color depth is the number of bits used to represent the color of a single pixel. Also known as bit depth or pixel depth.

Color Space: Digital cameras use defined color spaces to generate their images. The most common are sRGB and Adobe RGB. The color spaced used is recorded in the EXIF data in the image, so the Image Editing Software can display the colors correctly.

Color Filter Array (CFA): Typical image sensors only detect light sensitivity, not color, so a mosaic of tiny color filters (called a color filter array) is placed over the individual photosites (pixels) to capture color information. The most common kind is the Bayer Filter found in most modern DSLR's, which uses alternating rows of red/green and green/blue patches.

Compact Digital Camera: A small digital camera that does not take interchangeable lenses, often referred to as a 'Point & Shoot' camera.

CompactFlash (CF) : A flash memory card used to store images. CompactFlash is usually the standard card used by prosumer and professional digital cameras, due largely to its faster read/write speed compared to SD and other cards.

Compression: Reducing the size of an image file before it is written to the storage media (flash card, hard drive). There are two basic types of compression, Lossless, which retains all the original data and achieves limited compression, or Lossy, which produces smaller files, but throws away some of the image data. JPEG is a lossy format.

Continuous Autofocus: A setting where the autofocus system is continually tracking and refocusing to keep the subject in focus.

Continuous Mode: Also known as 'Burst Mode', a camera setting where the camera keeps taking pictures in rapid sequence, as long as the shutter release is depressed.

Contrast: The difference between the lightest and darkest tones in an image.

Control Panel: The top or rear monochrome LCD panels on DSLR's that display the shooting information (ISO, shutter speed, aperture, mode etc).

Crop: An in-camera or Imaging Editing Software function that allows you to select a portion of the image to keep, and discard the rest.

Crop Factor: The crop factor of a camera is the ratio of the diagonal length of the sensor to the diagonal of a 35mm negative. Full Frame cameras (like Nikons FX cameras) do not have a crop factor. Nikons DX cameras have a 1.5x crop factor. This ratio is also commonly referred to as the Focal Length Multiplier.

CRW, CR2: The Canon RAW file formats.

Curves: Image Editing Software tools that allow users to change color, contrast etc in a non-linear fashion.

Dark Frame: Also called Dark Frame Subtraction, a noise reduction technique where a camera takes a second exposure of a black frame after the camera takes an exposure, then the dark frame is subtracted from the first exposure to correct for extraneous noise in the sensor. The noise is often caused by hot pixels, which are photosites on the sensor with higher than normal charge leakage. On longer exposures, they can appear as bright pixels.

Dedicated Flash: A flashgun that is made to be used directly with a specific make or model of a camera.

Depth of Field (DoF): A measure of how much of the image is in acceptable focus. For landscape photography, it's typical to want as high of a depth of field as possible, to get both close objects all the way through to the horizon in focus. This is achieved by using a small aperture. Using a large aperture gives a much smaller depth of field, which is useful to blur out unsightly backgrounds or for portrait photography.

Depth of Field Preview: A button on the camera that closes down the aperture, to allow you to see the depth of field that the image will record through the viewfinder

Diffuser: A piece of opaque plastic that sits over the flash on a flashgun, to soften or scatter the light, resulting in less harsh shadows in the final image.

Digital Film: A term used to describe memory cards like ComfactFlash and SD (because they are used to store images in place of film).

Digital Zoom: A zoom performed using software on board the camera (as opposed to changing the focal length). The image is basically cropped, and then enlarged, often resulting in a loss of detail and sharpness.

Digitization: The process of taking analog data and converting it to digital, so it can be used on a computer.

Dioptre Adjustment: Some DSLR's have a dial near the viewfinder that allows the user to make small adjustments to tune the viewfinder image to their vision. This has no effect on the final image, it merely allows a user with slightly imperfect eyesight to view the image through the viewfinder more clearly.

Download: The term used to describe transferring image data from a camera to a computer.

DPI (Dots Per Inch) : See PPI (Pixels Per Inch).

DPOF (Digital Print Order Format): If supported by the camera, this allows you to select the images you want to print and how many prints to be made via the cameras menu, and it writes this information onto the memory card. Then printers or computers that support this can automatically read and act on this data.

DSLR, D-SLR (Digital Single-Lens Reflex): A digital camera that typically uses a mirror and pentaprism mechanism to allow the user to view the image as seen through the lens. When the shutter release button is pressed, the mirror folds out of the way (the 'clunk' sound that you normally hear from a DSLR), and the sensor captures the image. Usually has interchangeable lenses.

Dust Removal System: Some DSLRs come with dust removal systems – basically a system that vibrates the sensor to shake off dust, and some manufactures also offer antistatic coatings on the sensor to help prevent dust in the first place.

Dye Sublimation: Also known as Thermal Dye Sublimation, dye sublimation is a near photographic quality printing process where the color dyes are thermally transferred to the printing media.

Dynamic Range: The range of intensity of light a sensor can capture, usually measured in stops, between the brightest highlight and the darkest shadow that can be recorded. Parts of the image that are too bright for the sensor will appear white (blown highlights), and parts that are too dark will appear black, losing all detail in both these areas. Cameras currently have a much smaller dynamic range than the human eye, so if an image has very bright and very dark areas, like a shadowy scene on a bright day, it's not uncommon for either the bright areas (like clouds in the sky) to come out white with no detail, or dark areas (like shadows) to come out black with no detail, or both. This is because the dynamic range of the scene is greater than the dynamic range of the sensor.

DX: Nikons name used to designate its cameras with the smaller APS-C sized sensors.

Effective Pixels: The number of pixels actually used to capture the image. The sensor may actually have more pixels, the remaining pixels acting as the black reference point (also known as the 'dark current reading').

Exif (Exchangeable Image File) : A metadata format defined by JEIDA (Japan Electronic Industry Development Association), that is embedded into an image file (typically a JPEG or RAW file). The data typically includes detailed information about the camera and lens used, as well as settings used to take the picture. This information can be read later by image editing software and other software applications.

Exposure: The amount of light that hits the sensor as determined by the shutter speed and aperture size.

Exposure Bracketing: A camera feature that will take a series of images (usually 3, 5 or 7) with different exposures either side of what it believes to be the correct exposure. This helps ensure one image will have the correct exposure. This can also be done manually.

Exposure Compensation: A camera feature that you can set to tell the camera to either increase or decrease the exposure, based on what the camera believes is the correct exposure.

Exposure Meter: The part of the camera that performs metering, to determine the exposure (shutter speed and/or aperture) to be used.

Exposure Value (EV) : The exposure generated by an ISO (sensitivity), shutter speed and aperture can be represented by an Exposure Value. For example, 0 EV is defined as a 1 second exposure at f1.0 using ISO 100. 1 EV represents half the light of0 EV, 2 EV represents half the light of 1 EV and a quarter of the light of 0 EV. Every time EV increases by 1, the amount of light halves.

E-TTL: Canons exposure metering system, short for 'Evaluative Through The Lens'.

File Format: Digital photographs are stored in files, and there are several different types of file (knows as file formats). Most Point & Shoot cameras record images as JPEG files, and most DSLR's allow you to choose between storing the photo as a JPEG, in their own RAW file format (NEF files if it's a Nikon), and some support storing as TIFF files.

Fill in Flash: Also known is Fill Flash, it's the process of using a flash (either built into the camera or a separate flash gun) to light up the foreground subjects, usually in bright daylight. It's especially useful if shooting in heavy shadows or strongly backlit subjects, where without it the subject would appear too dark against a bright background.

Film grain: Small dots that show up on photographs made using film. The higher the speed (ISO) film, the larger these dots appear.

Filters: There are two kinds of filters:

1. Filters in image editing software or in the camera that allow you to make changes to the image (such as sharpening, brightness controls etc).
2. Filters that screw onto the front of the lens (or drop into the lens for some telephotos) either to protect the front element or to achieve an effect (such as polarizing filters, ND filters etc).

FireWire: A high speed data transfer interface known as the IEEE 1394 protocol, it's faster than USB2.0, but not as widely supported.

Firmware: A small software program that controls hardware. Most DSLR manufactures occasionally release new firmware updates to load into their cameras, which either fix problems, or add new functionality to the camera via its menu system.

Fixed Aperture: A term used to describe higher-end zoom lenses, where the maximum aperture remains constant regardless of focal length (for example, Nikons 70-200mm f2.8 keeps a maximum aperture of f2.8 all through the zoom range).

Fixed Focal Length: A lens that doesn't zoom. Also known as a prime lens.

Flash: A device that is either built into the camera, or a separate device called a flashgun, that emits a brief but bright burst (flash) of light to illuminate the picture, as the picture is taken.

Flash Exposure Compensation: A control on the camera or flashgun that allows you adjust the brightness of the flash, to lighten or darken the final image as needed.

Flashgun: An external device that can attach to the camera via its hot shoe, or can be used off camera (either on a bracket or fired remotely by the camera or flash controller), that provides a flash of light as the shutter is released to illuminate the picture. Flashguns can be extremely flexible and have a very complex set of controls. Many can communicate with the camera to get exposure readings, focal distances and so forth.

Flash Memory: The most common type of memory used by digital cameras to store data images, typically in the form of a flash memory card such as CompactFlash or SD. The cards can be deleted and re-written multiple times.

Flat Bed Scanner: An optical scanner that is attached to a computer to scan images such as photographs, creating a digital image of them.

Focal Areas: Most DSLR's now offer multiple focus areas. Depending on the focus mode selected, the camera can either select which focus area or areas itself, or the user can use the viewfinder to select which focus area to use.

Focal Length: The focal length of a lens is a number (stated in milimeters) that determines the magnification and angle of view the lens gives. A focal length roughly equivalent to the diagonal of the sensor is considered a Standard Lens (for for full frame/FX sensors, 40mm-50mm are considered standard, for APS-C/DX sensors, around 30mm is considered standard). If the focal length is less, the lens is considered a Wide Angle Lens, and if longer it's considered a Telephoto Lens.

Focal Length Multiplier: Most DSLR sensors have a smaller area than 35mm film, this effects the angle of view and magnification of the image relative to the sensor. While the actual focal length doesn't change, a lens has an effective focal length based on the sensor size – this is the equivalent focal length that would be required by a 35mm camera to give the same field of view or magnification. This number is called the Focal Length Multiplier. Full frame DSLR's like Nikons FX format don't have a focal length multiplier since the sensors are approximately the same size as a 35mm negative. Nikon's smaller DX format has a Focal Length Multiplier of 1.5x – so a 200mm lens on a DX camera has the same field of view as a 300mm lens on a 35mm camera. Canon's entry level DSLR's have a multiplier of 1.6x, so a 200mm lens has an effective focal length of 320mm on those bodies.

Focus Assist: A feature of some DSLR's that send out light (either normal or Infra Red) to light up the subject to assist the autofocus mechanism in low light conditions.

Focus Lock: Pre-focusing on a subject then using the focus lock before recomposing/re-framing the picture. Focus lock can usually be set up as a half shutter press, or sometimes as a separate thumb operated button depending on the camera.

Focus Ring: A ring on the lens body that allows manual focusing.

Four-Thirds: A lens mount, sensor size and communication protocol standard supported by Olympus & Panasonic, with the aim of being able to mix lenses and bodies between different manufacturers.

Foveon Sensor: See X3 Sensor.

Frame: A single picture or image. Movies consist of multiple frames.

Frame Rate: The number of frames, or images, that are captured or displayed each second. Movies typically run at 25 frames per second (fps) or faster, whereas DSLR's typically capture anywhere between 3 and 11 fps.

Full Bleed: Also known as borderless printing, the image extends to all 4 edges of the paper without leaving a border.

Full Frame: A sensor size that is approximately equivalent to a 35mm negative (36mm x 24mm). Both Nikon and Canon have full frame DSLR cameras.

FX: Nikons name used to designate its full frame cameras.

F-Stop: The standardized number used to specify the specify the size of the aperture/how much light the lens will let in. Lower numbers like f2.8 mean a larger aperture (more light), higher numbers like f22 let in much less light though a smaller aperture.

Gamma: A measure of the amount of contrast in the image.

Gamma Correction: Gamma correction controls the overall brightness of an image on a computer monitor – if not correctly adjusted, the image can appear too dark or too light.

Gamut: The range of colors available, either in an image or a device like a printer.

GIF: Mainly used for web graphics, a file format supporting images with limited color (max of 256 colors) and simple animations.

Gigabyte (GB) : A standard unit of computer memory, made up of 1024 MegaBytes.

Gradation: A smooth transition between colors.

Grey Level: The brightness value of a pixel representing it's lightness from black to white, usually represented by a number between 0 (black) and 255 (white).

Grey Scale: Black & White photography – all pixels are represented by shades of grey.

Guide Number: The power rating of a flashgun.

Halftone Image: Normally used for newspaper and magazine reproduction of images, using dots of various sizes to make up the image. Inkjet printers also use this technique.

Histogram: A bar chart that shows the distribution of tones within an image. On the far left is the black tone, and on the far right is the white tone, and the vertical axis shows how many pixels have that specific tone value. Values to the left of the histogram represent shadows, values in the center represent mid-tones, and values to the right are highlights. A well-exposed image will have values across the histogram. If the values are all to the left, the image is likely under-exposed, and if they are all to the right, over-exposed.

Hot Shoe: The slot at the top of a DSLR that allows you to mount a flashgun or other accessories.

HSM: Sigma's Hyper Sonic Motor focusing system, equivalent to Nikon's SWM and Canon's USM.

Hue: Hue is a term used to describe one of the main properties of a color, by using names such as 'red', 'blue' etc.

Hyperfocal Distance: A term often used in landscape photography. By stopping down the lens to maximize depth of field (or acceptable focus), and focusing the lens so that infinity is at one end of the depth of field, then the lens is said to be at its hyperfocal distance. Everything from approximately half the hyperfocal distance to infinity should then be in focus. Older lenses often had multicolored marks on the lens next to the focus ring, that matched the colors on the aperture ring, these indicated the depth of field to expect at a given aperture.

ICC Profile: The 'International Color Consortium' defines a standard guidelines for color mamagement. Most monitors, printers & scanners come with a driver disc or download that includes the ICC profiles for that device. They allow consistent reproduction of colors across multiple devices from different manufacturers.

IESP: The exposure metering system used on Olympus cameras.

iLink: The term Sony uses for the IEE-1394 FireWire data port found its camcorders.

Image Editing Software: Image Editing Software, such as Nikon CaptureNX and Adobe Photoshop, allow the user to manipulate, edit and improve photos. Many features are usually supported, ranging from sharpening, noise reduction, adjusting contrast, saturation and white balance, cropping and even removing or adding elements to the photograph.

Image Sensor: See Sensor.

Image Stabilization (IS): A method for reducing camera shake, usually built into the lens or body of a camera, or achieved digitally. This is most effective with telephoto lenses. Specifically, the IS designation on Canon lenses indicates they use Canons in-lens Image Stabilization system. Nikons equivalent is called VR (Vibration Reduction).

Infra Red (IR) : A wavelength of light invisible to the human eye. Some remote releases use IR to trigger the shutter release. Digital sensors are sensitive to IR light, so most contain a filter over the sensor to eliminate IR light. Several companies offer to convert camera bodies for IR Photography by removing this filter.

Inkjet: A type of printer that sprays microscopic dots of ink to paper to form images and text. Currently Inkjets produce the best quality prints from digital images for home/small scale use.

Interlaced: Used to describe an image sensor that gathers data by first processing the odd lines, and then the even lines.

Interpolation: Altering the size of the image (usually enlarging) by creating or removing pixels using mathematical re-sampling techniques. This often results in a decrease in image quality. LizardTechs 'Genuine Fractals' is generally considered the leading program in this area.

Intervalometer: Another term for Time Lapse Photography.

ISO: Based on the International Standards Organization's definition of the speed - or sensitivity - of color negative film, the term now refers to how sensitive the image sensor is to light. By making the sensor more sensitive to light (i.e. using a higher ISO number), the image can be captured with a higher shutter speed and/or smaller aperture. However, the higher the ISO, the more noise that may be visible in the image.

i-TTL: Nikons flash exposure system, supported by recent Nikon DSLRs and their SB-600, SB-800 and SB-900 flashguns.

Jaggies: See also pixelization - visible jagged edges/steps along lines in a digital image.

JPEG, JPG (Joint Photographic Experts Group): The most common type of image file format. It is a lossy format, meaning that image data is lost to achieve smaller data files, and frequently editing and resaving JPEG files degrades the image quality more quickly. Many cameras that output JPEGs do give you some control over the JPEGs quality – settings like “Fine" give a larger image file with less image degradation.

JPEG 2000: A newer JPEG standard featuring higher compression with less image quality loss. It has yet to be widely adopted.

Keylight: The term for the main light source that will cause predominant shadows in an image.

Kilobyte: A standard unit of computer memory, made up of 1024 Bytes.

Kit Lens: A lens offered as part of a kit with a DSLR body. Kit lenses are not always the best quality, but do offer a very cost effective way for users to get into DSLR photography.

Lag: A delay – examples include shutter lag, autofocus lag (a delay while the camera acquires focus lock) and processing lag (a delay while the image is processed and written to the memory card).

Landscape: A camera mode that selects a small aperture (to maximize depth of field), and sets focus near infinity for landscape photography.

LCD (Liquid Crystal Display) : The display on the back of a DSLR that lets you preview shots and operate menus, and a type of flat panel display for computers.

LED (light Emitting Diode) : The small indicator lights used on cameras and other electronic devices.

Lenses: Most DSLRs have interchangeable lenses – you can take the lens of the front of the camera, and put on a different lens. Lenses are typically either primes (fixed focal lengths) or zooms (variable focal length), and go from extreme wide angles to extreme telephotos.

Li-ion: Lithium ION – a type of rechargeable battery favored by camera manufacturers. A Li-ion battery typically operates better at lower temperatures and holds a charge for longer than Ni-MH battieries, however they are a little more expensive.

Live View: Common on Point & Shoot cameras but a recent addition to modern DSLRs, giving the user the ability to compose and view the image on the LCD, instead of through the viewfinder, before taking the picture.

Lossless Compression: A compression technique that makes the image file smaller without discarding any image data. With the Nikon D300 & D3, Nikon introduced a lossless compressed RAW file format.

Lossy Compression: A compression technique that makes the image file smaller, and in the process discards some image data. JPEG is an example of lossy compression. Lossy compression files are typically smaller than lossless compression files.

Low Pass Filter (LPF): Most DSLRs have a Low Pass Filter (also known as an anti-aliasing filter) in front of the sensor to help eliminate problems with moiré.

Mac: An Apple Macintosh computer.

Macro: A Macro lens is a lens that can focus extremely closely, allowing pictures to be taken at a 1:1 reproduction ratio (e.g. a half inch long object will have a half inch long image captured on the sensor).

mAh: Short for milliAmpere Hour – the measure of capacity of a battery or the power consumption of a device. 1 mAh means the battery can supply (or the device will use) 1 milliAmp for a full hour.

Matrix Metering: A metering option that takes exposure readings at multiple points across the frame to determine the final exposure. Also known as Multi Zone or Multi Pattern Metering.

Megabyte (MB) : A standard unit of computer memory, made up of 1024 KiloBytes.

Megapixel (MP) : A standard unit of image resolution, made up of one million pixels.

Memory Card: A removable solid state card that is used in digital cameras to store image data. Available in multiple styles, including CompactFlash and SD, and multiple capacities.

Memory Stick: A flash memory card by Sony, used primarily on Sony digital cameras.

Memory Stick Pro: A faster version of Sony's Memory Stick, first introduced in 2003.

Metadata: Data stored within the image file that details about the exposure, including camera settings, while balance, ISO, focus, and much more. The two main types of metadata in digital images are the Exif standard and and DPOF (Digital Print Order Format) standard.

Metamerism: Two different colors appearing the same under certain lighting conditions, and different under others.

Metering: Calculating the correct exposure for the image using existing light. The four different kinds of metering are Spot (metering off a small circle in the center of the image), Average (averaging the exposure across the image), Center Weighted (similar to average, but giving more importance to the center of the image) and Matrix (metering from several distinct points on the image).

Microdrive: Miniature hard drive packaged in a CompactFlash Type II case. Made by IBM & Hitachi, they consume more power than CompactFlash cards.

Mirror: A DSLR has a mirror in front of the sensor, that directs light through the pentaprism and into the viewfinder. When the shutter release is pressed, the mirror flips up out of the way allowing the light to fall on the sensor instead.

Mirror Lock-Up: A feature of some DSLR's that locks the mirror in the “up" position, allowing access to the sensor for cleaning, or to enable Live View functionality, or to reduce camera shake caused by the mirror moving on long exposures.

MMC (Multi Media Card): A flash memory card identical in size and shape to the SD memory cards.

Moiré: An unwelcome pattern in a digital image caused when the detail in the subject exceeds the resolution of the camera. Usually causes a colorful wavy, rainbow or checkerboard pattern.

Motion JPEG: A video clip made up a sequence of JPEG images.

Mount: The physical connection between the lens and the camera body, with each manufacturer having its own mount (so you can only use lenses designed for that camera). The mount also typically has the electrical connections needed for the camera to communicate with the lens.

MOV: File format for Apple QuickTime Movies.

Movie clip: A sequence of motion captured in one of the movie file formats.

MPEG: Stands for Motion Picture Expert Group, an industry standard compressed movie file format.

MPEG-EX: A Motion JPEG movie file created by Sony cameras.

MPEG-HQX: A high quality, full screen movie format used by Sony.

MPEG-VX: Another Sony movie format, supporting full screen (640x480) at 16fps, or 30fps in VF Fine mode.

Multi-Pattern Metering: See Matrix Metering

Multi Point Focusing: An autofocus system that uses several points in the frame to determine the correct focus.

NAS (Nikon Acquisition Syndrome): A highly contagious, incurable illness, normally beginning innocently enough by buying, inheriting (or in some cases, merely just borrowing) a Nikon camera. Shortly afterwards, you start trying to justify to yourself, your spouse, and/or your bank manager, why you need another lens. You give in and buy it. It's followed by another. And wouldn't a flashgun be nice? How about that battery grip? Then you start looking at the pro lenses and you sink to the next level. You then need to upgrade to the newest Prosumer body. You try to fight it, and join a support group like nikonians.org or dpreview.com, but that only makes it worse. Then Nikon releases a shiney new wide angle. Then a new pro body comes out. One of your lenses gets upgraded with a better vibration reduction and nano coating. Your will to resist is broken, NAS is in full control. While rarely fatal, usually results in severe lightening of the wallet, and potential spousal problems.

Native File Format: The default file format for a software application or digital camera.

NEF (Nikon Electronic Format): The RAW image file format used by Nikon.

NiCd: Nickel Cadmium rechargeable batteries, rarely used since the introduction of NiMH batteries.

Nikon: Along with Canon, one of the two leading DSLR manufacturers.

NiMH: Nickel-Metal Hydride rechargeable batteries.

Noise: A random pattern of unwanted artifacts/pixels that degrades the image quality, as grain did to film. Noise tends to be worse in low light and incorrectly exposed pictures, and also tends to increase as the cameras ISO setting is increased.

Noise Reduction: The act of removing digital noise from images using software – either on camera or during post processing. Usually results in a small loss of sharpness, which is often preferable to the keeping the noise.

NTSC: Video format used in the U.S. and Japan.

OEM (Original Equipment Manufacturer): Typically a company that uses component of a second company in it's product, or sells someone else's product under it's own brand.

Optical Resolution: The optical resolution of a lens is the ability of the lens to resolve detail, and is ultimately limited by diffraction, which is dependant upon aperture. The optical resolution of a sensor is usually expressed in line pairs per millimeter (lppmm).

Optical Zoom: A zoom with a variable focal length (as opposed to a digital zoom, which basically crops and enlarges the image using software).

ORF (Olympus RAW format) : RAW file format used by modern DSLRs from Olympus.

Orientation: The direction the camera is held – Landscape has the long side of the image on the horizontal, and portrait has the long size of the image on the vertical (achieved by rotating the camera 90 degrees when taking the picture)

Orientation Sensor: Some cameras have sensors to detect when pictures are taken in portrait format (camera held sideways), so they can auto-rotate the image when playing back with the cameras LCD or on a computer.

Overexposure: An incorrectly exposed image that is too bright, causing a loss of detail in bright areas.

PAL: Video format used mostly in Europe and other places outside of the U.S. and Japan.

Palette: The selection of colors available in the image or for the monitor. For 24 bit images, the palette consists of approximately 16.7 million colors.

Panorama: An extreme wide angle view, often made by taking several images and stitching them together.

Parallax: The effect when the viewfinder sees a different image to the sensor/film – usually only a problem at close range. SLR cameras and cameras that let you compose the image on the viewfinder do not have problems with Parallax.

PC (Prontor/Compur) Connector: A standard 3mm coaxial cable//connector used to synchronize the flash with the camera, typically used when the flash is not mounted on the cameras hot shoe/accessory mount bracket.

PCMCIA: Supported by most modern laptops, PCMCIA (Personal Computer Memory Card International Association) Cards are available to read most flash card formats (including CompactFlash, Secure Digital, SmartMedia and more), allowing easy transfer of images from memory card to computer.

Pentaprism: The prism sits on top of SLRs, and reflects the light from the mirror to the eyepiece.

Photosite: A light sensitive cell on the sensor, typically one photosite records one pixel in the final image. With Bayer sensors, the photosite records one color only. With Foveon X3 Sensors, the photosite is layered and records all three RGB colors.

PictBridge: A standard for printing directly from the digital camera to the printer without using a computer.

PIM (Print Image Matching) : Epson's standard for embedding color and printing information for digital cameras – many manufacturers embed the PIM information in the Exif header of JPEG images.

Pincushion Distortion: Usually found with cheaper lenses and some zooms, the image is compressed towards the center. For example, a photograph of a rectangular object would have its sides bow towards the center. Can be fixed with most image editing software.

Pixel: Short for 'Picture Element', a pixel is a single point of a digital image, representing a value for color, luminance and intensity. Images are made up of thousands or millions of pixels.

Pixelization: This is when curves or angled lines in images have a “stepped" appearance. Also known as 'Jaggies'. Higher resolutions and anti-aliasing software both decrease this effect.

Plug-n-Play: A Microsoft Windows feature that allows automated installation and connection of peripherals when they are connected to the computer, either fully automating the connection or prompting the user to complete the process.

PNG (Portable Network Graphic) : A compressed image format, that typically generates smaller files than JPEG, but also can support lossless compression.

Point and Shoot: A simple to use camera that does pretty much everything automatically for you.

Polarizer (Polarising Filter) : A filter that helps eliminate glare, and can darken skies by polarizing the light entering the lens. Modern cameras require circular polarizers (as opposed to linear polarizers) for the autofocus to work correctly.

Post Processing: Using image editing software such as Nikon CaptureNX or Adobe Photoshop to adjust digital images (correct colors, cropping, sharpening etc).

Posterisation: A special effect that reduces the number of tones in an image, giving a surreal effect.

PPI (Pixels Per Inch) : As with DPI (Dots Per Inch), a measurement to describe the size of a printed image. Computer monitors are typically 75 PPI, whereas a printout is usually 300 PPI (making a smaller, but more detailed printout).

Pre-Flash:A brief flash that comes before the main flash, so the camera can measure the power required for the main flash. Also used for red-eye reduction.

Prime Lens: A lens with a fixed focal length (as opposed to a zoom lens), and because of this often offer better image quality, more compact and have faster apertures than their zoom equivalents.

Programmed AE: An Automatic Exposure mode where the camera chooses both shutter speed and aperture for the shot.

Prosumer: Refers to a manufacturers mid range of cameras, aimed at serious amateurs or professionals looking for cheaper cameras or backup cameras. For example, with Nikons current line up, the Consumer DSLRs have two digit numbers (D40, D80 etc), the Professional DSLRs have single digit numbers (D2, D3 etc), and the Prosumer models have 3 digit numbers (D300, D700 etc).

Purple Fringing: A purple “rim" that sometimes appears around high contrast areas in digital images. This is usually a form of chromatic aberration, more common with cheaper lenses, and can usually be fixed with image editing software.

QuickTime: Apple Computers image and video framework. Many digital cameras that output video do so using Apples QuickTime format.

QVGA: Quarter VGA resolution – 320 by 240 pixels – a popular low resolution video format.

Rangefinder: A camera with two separate lenses, one to focus light on the sensor/film, and another for the viewfinder that allows the user to determine the subject distance (the range-finder), to allow sharp focus.

RAM: Random Access Memory – the common computer memory, also found in modern cameras.

RAW: RAW files contain the image data taken directly from the cameras sensor, along with detailed shooting data, and have not been processed by the camera. This allows the image to be post-processed using image editing software like Nikon CaptureNX or Adobe Photoshop. Shooting RAW and post processing typically gives the most flexibility and best possible final quality image, however takes time and effort compared to shooting other formats like JPEG. Nikon's raw format is called NEF.

Red-Eye: Red looking eyes in photographs, caused by the cameras flash reflecting off the retina at the back of the eye. The closer the flash to the lens, the more pronounced the effect.

Red-Eye Reduction Mode: A special flash mode that fires one or more flashes before taking the picture. This causes the persons iris to contract so less light gets into the eye, reducing the red-eye effect.

Render: The process of building or displaying the final image from it's components (for example a RAW file, then applying sharpening and other adjustments to get the final image).

Resize: To make an image larger or smaller.

Resolution: For digital photography, the number of pixels in an image, or on a sensor or monitor, usually measured in megapixels. The higher the resolution, the more data, and therefore fine detail in the image.

RGB (Red, Green & Blue): The primary colors, all other colors can be represented by mixes of red, green and blue. Every pixel in an image can represented by its values for these three colors.

Saturation: The intensity/vividness of a color, and can be modified using image editing software.

Scanner: An optical device that creates a digital image from a flat object like a photograph.

Scene Modes: Many DSLR's have Scene Modes such as Landscape, Portrait, Sport & Indoor that quickly set up the camera for a certain style of shooting. For example, a Sports mode would tend towards a higher shutter speed to freeze action, whereas a Landscape mode would tend towards a smaller aperture to maximize the depth of field and get more of the photo in focus.

Screwdriver lens: A term used to describe older autofocus lenses that couple with an autofocus motor in the camera body, such as the older Nikon AF series lenses (as opposed to the Nikon AF-S lenses that use a Silent Wave Motor instead). Some of the more recent consumer DSLR's, such as the Nikon D40 and Nikon D60, no longer come with an AF motor in the body, so these cameras cannot autofocus the older screwdriver lenses.

Secure Digital (SD): A solid state memory card, extremely popular in consumer grade DSLR's, Point & Shoot cameras, and other electronic devices. They are much smaller and slower than the CompactFlash cards that are used in the pro cameras.

Self Cleaning Sensor: A recent development that vibrates the sensor in a DSLR to try and shake off dust. Current models do help somewhat, but most users report they are not a substitute for a full sensor clean.

Self Timer: Many cameras allow you to set a time delay (usually in seconds) before the shutter is released automatically. This gives the photographer time to move in front of the camera so they can be in the image, and is also of use when using a tripod and mirror lock-up features of a camera to help eliminate camera shake.

Sensor: An electronic chip that is sensitive to light and converts the image to digital form, eliminating the need for film in the camera. The two main types of sensor are CCD (Charge-Coupled Device, used mainly in smaller devices) and CMOS (Complementary Metal Oxide Semiconductor, used mainly in higher end DSLR's). There are other kinds of sensor, including JFET (Junction Field Effect Transistor) and Foveons X3 Sensor, but these are rarely used.

Sepia: A brownish monotone effect often seen in images from the 19th and early 20th centuries. Most image-editing software packages allow you to achieve this same effect.

Sharpening: Increasing the sharpness of an image using on camera or image editing software. Typically sharpening gives more distinct edges to lines and areas in a digital image.

Sharpening Artifacts: These generally appear as halos (usually black or white) around high contrast areas of the image as a result of sharpening an image. This is generally worse using in-camera sharpening than when using image editing software.

Sharpness : Images with better defined and smoother edges are said to be sharp, as opposed to soft. Sharp images require accurate focus and eliminating or minimizing camera shake.

Shutter Delay/Shutter Lag: The time delay between pressing the shutter release and the image being actually taken. With modern DSLR's, the shutter delay is minimal, fractions of a second, but many Point & Shoot cameras have significant delays while the camera focuses, sometimes causing the user to miss the picture they wanted.

Shutter Priority AE: Shutter Priority Auto Exposure allows the user to select the shutter speed, and the camera then selects the aperture automatically based on lighting conditions. Shutter priority is commonly used for sports and wildlife photography when you need to keep the shutter speed high to freeze the action.

Shutter Release: The button you press to take the picture. Often half pressing the Shutter Release activates the autofocus, auto exposure and vibration reduction, and a full press is required to actually take the picture.

Shutter Speed: The amount of time that the shutter actually allows light to fall onto the film or sensor, typically measured in fractions of a second. The faster the shutter speed (e.g. 1/1000 of a second), the better to freeze action and reduce camera shake. Tripods allow slower shutter speeds (in some cases measured in seconds or minutes), which allow the creation of such effects as blurred waterfalls.

Skylight Filter: Also known as a UV filter, filters out Ultra Violet light and prevents it hitting the film or sensor. Useful on film cameras to prevent a bluish tint during outdoor photography, but of little use on digital cameras with auto white balance.

Slow Sync: A flash mode that allows slower shutter speeds and fires the flash just before the shutter closes, allowing better exposure of distant objects behind the flash-lit foreground.

SLR (Single Lens Reflex): A camera design where the user sees the exact image through the lens from the viewfinder, allowing the user to see the image before it is recorded. See also DSLR

SmartMedia: Another form of flash memory card, that is no longer used.

Spot Metering: The cameras exposure meter relying just on a small circle in the center of the image to expose the picture. Useful for exposing high contrast images, where the background exposure is less important (like the moon against a black sky).

Stereoscopic Photography: A way to create a 3D image from 2D photography, by using two cameras spaced a short distance apart to take two pictures at the same time.

Stitching: Using image editing software to combine a series of images to create a larger image, typically a panoramic photo.

SuperCCD: Image sensors used in Fujifilm's digital cameras.

SVGA (Super VGA): A monitor or image with a resolution of 800 by 600 pixels.

SWM (Silent Wave Motor): An electric motor used in some of Nikons more modern lenses (the lenses are marked AF-S), which use tiny vibrations to create the rotation or movement needed to focus the lens. Most major camera manufacturers utilize similar technology, and each uses their own brand. These types of lenses tend to be faster, quieter and more accurate than older autofocus lenses, which relied on a focusing motor in the camera body rotating a 'screw' in the lens.

Telephoto: A focal length of lens that gives a much narrower angle of view than a standard lens, making objects appear closer through the viewfinder.

TFT (Thin Film Transistor) : A type of color, high resolution LCD display.

Third Party Lenses: Lenses made by a company other than the camera manufacturer, for example Sigma and Tamron. Third Party Lenses are usually significantly less expensive than the camera manufacturers lenses, and are usually almost as good, and in some cases as good. However camera manufacturers do not always fully publish interfaces, so there is no guarantee a third party lens will be full compatible with future bodies and features from the camera manufacturer.

Thumbnail: A small, low resolution version of an image, allowing rapid viewing/sorting of multiple images.

TIFF (Tagged Image File Format): A lossless image file format that retains the full image detail, unlike JPEG files which give up image data to achieve higher compression and smaller but lower quality image files. Extremely popular format for Print Publishing.

Time-Lapse: Also known as Interval Recording, the process of capturing a series of images at preset intervals. The classic example is photographing a flower once per minute to get a full sequence as it opens.

Tonal Range: The number of tones available to describe the dynamic range of an image. The higher the tonal range, the more colors available between the brightest highlight and darkest shadow.

True Color: Images stored or displayed at a depth of 24 bits per pixel (representing approximately 16.7 million possible colors).

TTL (Through The Lens) :Applies to the viewfinder image, metering, autofocus or any other function that occurs 'Through The Lens'. The TTL viewfinder found on SLR's and DSLR's allows the user to see if the image is in focus, the effect of any filters, depth of field and so forth.

Tungsten Lighting: The most common form on indoor domestic lighting, having a color temperature of 3200 Kelvin, which is warmer than normal daylight.

Twain: Standing for 'Technology Without An Industry Name', twain is a protocol for exchanging information between applications, and is commonly used by digital cameras and scanners to allow them to communicate with PC's.

Under Exposure: Insufficient light entering the camera causing the final image to be too dark, usually caused by incorrect metering.

Unsharp Mask: A software tool available in most image editing packages (including Nikon CaptureNX and Adobe Photoshop) that increases apparent sharpness of an image.

USB (Universal Serial Bus): A data port found on most computers and cameras that allows the transfer of data between the camera and computer. Data transfer rates up to 1.5 Megabytes per second can be achieved with equipment supporting USB 1.1, and the high speed USB 2.0 supports up to 60 Megabytes per second. A USB 3.0 is rumored for late 2008, possibly supporting up to 600 Megabytes per second.

USM (Ultra-Sonic Motor): An electric motor used in some of Canons higher end lenses, which use tiny vibrations to create the rotation or movement needed to focus the lens. Most major camera manufacturers utilize similar technology, and each uses their own brand – Nikon has SWM (Silent Wave Motor), Sigma has HSM (Hyper Sonic Motor), Minolta & Sony has SSM (SuperSonic Motor) etc. These types of lenses tend to be faster, quieter and more accurate than older autofocus lenses, which relied on a focusing motor in the camera body rotating a 'screw' in the lens.

UV Filter: A filter that absorbs Ultra Violet light rays without changing the exposure for outdoor photography. Commonly used when shooting film, because the UV rays that are invisible to the naked eye could be recorded on film, which is more sensitive to ultra violet, causing the image to have a bluish tint. They have little to no effect on DSLR's since the cameras auto white balance system adjust to the color temperature, although many people still keep them on their lenses at all times to protect the front element from dust and scratches.

UXGA (Ultra eXtended Graphics Array): A video monitor or image having a 1600 x 1200 pixel resolution.

VGA, Video Graphics Array: A video monitor or image having a 640 x 480 pixel resolution.

Video Out: A connector on a video-capable digital camera or camcorder that allows you to hook up and display video directly to the TV. Typically supports one or more of PAL, NTSC or HDMI formats.

Viewfinder: An eye-level device that you look through to preview the image before taking the picture. The viewfinder also often displays other critical information, for example focus areas superimposed on the image, and shutter speed, battery life, metering information etc either under or to the side of the image.

Vignetting: The darkening of the corners of an image, usually caused by a zoom lens, or using the wrong filter or lens hood which restrict light at the corners and/or edges of the sensor. It can also be used as an effect during post processing.

VR (Vibration Reduction) A technology designed to reduce camera shake, by either having an element in the lens move, or having the sensor move in camera to counter movement while the picture is taken. While not foolproof, it's not uncommon for VR to allow the user to shoot 2-3 shutter speeds slower than they otherwise could while still getting sharp pictures.

White Balance: The camera control that allows you to adjust the color balance of the image to make shots look more natural under different lighting conditions (e.g. bright daylight, tungsten lighting, fluorescent room lighting etc all need different white balance settings). Virtually all digital cameras have an auto white balance feature, whereas film cameras rely on selecting the correct film, and then using filters to further adjust the white balance. Higher end DSLR's allow you to manually set or calibrate the white balance against a white card, while less expensive models generally come with presets like 'Sunny', 'Cloudy', 'Fluorescent' etc. If your DSLR is set to shoot in a RAW format (like Nikon's NEF), then the wide balance can be adjusted/corrected later using Nikons CaptureNX or Adobe Photoshop.

Wide Angle: The focal length of a lens that gives you a wider angle of view than standard lenses. For 35mm film cameras, any lens with a focal length less than 35mm is considered wide angle. For APS-C cameras (like Nikons DX cameras or Canons 1.6x cameras), 24mm or less is generally considered wide angle due to the crop factor.

X3 Sensor: The Foveon X3 sensor is a CMOS sensor for digital cameras, that allows each pixel to capture all three primary colors, red, green and blue. Very few consumer cameras currently use this sensor (just Sigma and Polaroid), most use Bayer sensors (where a filter covers the sensor, so each pixel only sees one of red, green or blue and the camera then applies an algorithm to give each pixel a full RGB value.

xD Memory Cards: Also known as Extreme Digital memory cards, and smaller than SD memory cards, these are flash memory cards designed specifically for digital cameras. Introduced by Olympus & Fujifilm primarily for use in their cameras in July 2002, they are now sold under numerous brands.

XGA: Short for Extended Graphics Array, with a resolution of 1024 by 768 pixels.

Yashica: A Japanese camera maker that began in 1949 in Nagano, Japan as the Yashima Seiki Company, and introduced it's first camera in 1953. Over the years it also produced cameras under the brands Contax and Kyocera, until production was halted in the face of intense competition in 2005.

Zoom Lens: A zoom lens allows the user to vary the focal length (i.e. 'zoom in' to make an object appear larger in the viewfinder, or 'zoom out' to make it smaller), as opposed to prime lenses which have fixed focal lengths. This gives the user the ability to 'zoom in' or 'zoom out' to better frame the shot, and reduces the number of lenses that have to be carried. Traditionally zoom lenses have produced inferior quality images to primes, but with modern technology this no longer always the case.

Zoom Ring: The ring on the barrel of a zoom lens that the user rotates to change the focal length (i.e. 'zoom in' or 'zoom out').