A Glossary of Photographic Terms
This Digital Dictionary is on hand for whenever you come accross a photographic term you don't understand. Refer to it often and you will quickly master the "language" of digital photography, particularly useful when reading magazines or learning editing programs.
AC Power - Alternating Current which is used to operate your digital camera directly from the mains supply rather than a battery. Sometimes supplied, but normally requires additional expense.
AE - Auto Exposure. When the camera is set to this mode, it will automatically set all the required modes for the light conditions. I.e. Shutter speed, aperture and white balance. The 3 types are:
AF. Auto Focus. All digicams and most modern SLR lenses have this function now. The lens automatically focuses on the subject as quick as the eye. The only difference is that with an SLR you can normally select manual focus if necessary.
Angle of View. This is calculated by the focal length of the lens and the size of the image sensor. The 35mm equivalents differ according to the sensor size.
Aperture. The lens opening that allows more, or less light onto the sensor formed by a diaphragm inside the actual lens.
Aperture Priority AE. When using this mode, the user selects the aperture giving control over the Depth of Field. A large aperture letting more light in gives a small depth of field, meaning not much will be in focus. Whereas a small aperture, not letting much light in, will give a greater depth of field or more will be in focus from the front to back of the image.
Aspherical Lens. A lens with edges flattened so that it is not a perfect sphere. These produce a much superior image.
Automatic Exposure. The camera sets the shutter speed and aperture for the correct exposure according to the light.
Automatic Focus. The lens on the camera focuses automatically when the shutter is half pressed. The viewfinder normally has focussing points shown to assist the user in knowing what will be in focus.
AVI. Movie clip in Windows AVI format. A lot of digicams now have this feature for producing small video clips.
AWB. Automatic White Balance. Most digital cameras have this feature where the camera sets the white balance. Override is available in most DSLR's.
B & W . Abbreviation for Black and White.
Back Lit. Meaning the subject is lit from behind which can cause underexposing. Is also used for portrait photography for special effects and bringing catchlights to the hair.
Backlight. The illumination for a colour LCD display on digital cameras or phones.
BMP. Bitmapped graphics file format which is popular with Windows PC's. It is an uncompressed file format like a TIFF.
Borderless. Quite simply, this means a printed photograph with no border around it.
Bracketing. Can apply to flash or exposure. It is used to create usually 3 photographs. One photo is exposed by the cameras meter automatically, one under exposed and one overexposed by a predetermined number of stops. Also "exposure bracketing".
Brightness. Value of a pixel in a digital image giving its value of lightness from black to white, with o being black and 255 being white.
Bulb. Term used for a long exposure setting normally more than 30 seconds. The start of the exposure is made by pressing the shutter, only ending when the shutter button is released. Excellent for night photography and a remote release is recommended to prevent camera shake as you press the shutter button.
Burst Mode. Also know as continuous mode or "Auto wind" on older SLR's. However, today's Digital SLR's have bust modes of up to 8 frames per second. Great for sports and action shots.
Calibration. The act of adjusting the colour of one device to match that of another. For example when you match the calibration of your screen to that of your printer to ensure what you see is what you print. It is also used in the film SLR's Canon EOS-3 and EOS 5 which have eye-controlled focussing. You calibrate the cameras focussing to where your eye is looking in the viewfinder. (Some fighter planes also have this. The missile follows the trajectory of the pilot's eye).
Card Reader. Used for transferring data from your flash memory card to your PC. A better way of transferring your image files than connecting the camera to your PC. Sometimes the cameras circuitry can become corrupt. Better to fry a memory card than your camera.
CF. Compact Flash card. Used in your digital camera to record images. Storage space ranges from 16MB up to 12GB. A company in Japan is currently developing a CF card that will store 2TB of information or 2,048 Gigabytes.
Chroma. The colour of an image element or pixel. A chroma is made up of saturation plus the hue values, but is separate from the luminance value.
Chromatic Aberration. Also known as purple fringing. It is fairly common in 2MP digital cameras and above, especially if they have long telephoto lenses. You can see it when a dark area is surrounded by a highlight. In between the dark and light, you may see a band of purple pixels that shouldn't be there. There are ways of removing this which I have covered in the Photoshop section.
CMYK. Cyan, Magenta, Yellow and BlacK. Colours used by most printers to produce your prints. Colour shifts can be caused when the colour management system tries to convert your PC's RGB files to CMYK. Before printing, try converting your images to CMYK and see what the difference is.
Colour Balance. The accuracy with which the colours captured in the image, match the original scene.
Colour Cast. This is a very unwanted tint of one colour in an image caused by the wrong amount of Cyan, Magenta and Yellow. It can be corrected using your editing software.
Colour Correction. To correct or enhance the colours within an image.
Colour Depth. Digital Images can approximate colour realism but the process is referred to as colour depth, bit depth or pixel depth. Most modern computer displays use 24 bit true colour. It displays the same number of colours that the human eye can discern, about 16 million.
Colour Space. Digital cameras use known colour profiles to generate their images. The most common is sRGB or Adobe RGB. This along with all of the other camera data is stored in the Exif header of the Jpeg file. The colour space information ensures that graphic programs and printers have a reference to the colour profile that the camera used at the time of taking the exposure.
Compact Flash. See CF. This is the most commonly used type of memory. It is small, removable and available in a wide range of sizes up to 12GB.
Continuous Autofocus. As it says. The auto focus system is continuously working on focussing on the subject.
Contrast. The measure of rate of change of brightness in an image.
Dark Frame. A noise reduction process where a camera takes a second exposure of a black frame after the camera takes a long exposure image. The image noise is easily identified in the black frame shot and is then electronically removed from the actual image. This helps to reduce the amount of hot pixels that normally show up in long exposure shots from digital cameras.
Dedicated Flash. An Electronic Flash Unit that is made to be used directly with a specific make or model of a camera. Canon, Nikon Minolta and Olympus for example, all have electrical contacts in the hotshoe which passes TTL (through the lens) metering and AF range information to and from the flash unit or speedlight. Youcannot interchange flash units and cameras. I.e. a Nikon speedlight on a Canon camera.
Depth of Field. (DOF). The range of items in focus in an image. This is controlled by the focal length and aperture opening of a lens. A large or wide aperture gives a shallow depth of field (not much range in focus) and a smaller or narrow aperture give a large depth of field (more range in focus).
Digital Film. Quite simply that. Solid state flash memory cards in place of emulsion film.
Digital Zoom. A digital magnification of the centre 50% of an image. These give less than sharp images because the new zoomed image has been interpolated. Don't be swayed by the incredible 500% zooms on some cameras, the images won't be really acceptable. The optical zoom gives much more clarity to an image.
DOF. Abbreviation of Depth of Field.
Download. Term used for the transference of image data from the camera to your computer. Can be done via a serial port or the faster USB port. Downloads can also be done via Bluetooth or Infra-red without the need for cables.
DPI. Dots per Inch. This is a measurement value used to describe the resolution of a display screen or that of a printer
DSLR. Digital Single Lens Reflex (SLR). Camera with interchangeable lens.
DVD. Digital Versatile Disk. DVD is DVD recorded on a DVD-R or DVD-RW disc.
Dynamic Range. This is a measurement of the accuracy of an image in colour or grey level. More bits of dynamic range results in much finer gradations being preserved.
EV. Exposure Value. The ability to override the auto exposure system to under or over expose the image.
Exposure. Amount of light that hits the image sensor of film controlled by the shutter speed and aperture.
Exposure Bracketing. Camera will take 3 or 5 images and varies the exposure up or down for each photograph ensuring at least one will be well exposed.
Exposure Compensation. You can lighten or darken the image by under or over exposing the image. (EV compensation).
F-Stop . Number indicating the size of the aperture. It is an inversely proportionate number as in F2.8 is a large opening and F16 is a small opening.
File. A collection of information like data, text or images which are saved on a CD. DVD or hard drive.
File Format. Type of program or data file. Includes JPEG, TIFF and BMP
Fill in Flash. See Fill in Flash
Fixed Aperture. Aperture remains constant regardless of the lens' focal length. I.e. The Canon "L" series have a constant fixed aperture when zooming.
Fixed Focal Length. Basically a non zoom lens. 100mm, 50mm, 200mm etc.
Flat Bed Scanner. Optical Scanner in which the original image remains stationary while the CCD sensors pass over or under it. The scanned image is held flat by the lid hence the name.
Focal Length. A lens' angle of view. Such as Wide angle, standard or telephoto.
Focus Lock. Focus lock means pre-focussing the subject and re-framing by moving the camera. This is done by half pressing the shutter to focus and fully pressing to expose. Done to ensure crisp, sharp eyes for example.
Frame. One of many still pictures that make up a video.
Frame Rate. Number of frames that are shown or sent each second. Live action is around 30 frames per second.
Gamma . Measure of the amount of contrast in an image according to the properties of a gradation curve. High contrast = High Gamma and Low = Low.
Gigabyte (GB). A gigabyte is a measure of computer memory or disk space consisting of about one billion bytes (a thousand megabytes). The actual value is 1,073,741,824 bytes (1024 megabytes).
Gradation. A smooth transition between black and white, one colour and another or colour and no colour.
Grey Level. This is the brightness level of a pixel representing it's lightness from black to white. It is usually defined as a value from 0 to 255, with 0 being black and 255 being white.
Grey Scale. A term used to describe an image containing shades of grey rather than colour. Most commonly referred to as a black and white photograph.
Halftone Image. An image reproduced through a special screen made up of dots of various sizes, to simulate shades of grey in an image. Normally used for magazine or newspaper reproduction of images. It is also how modern inkjet printers work. Half toning or dithering are the methods used to produce a smooth gradation of colour versus distinct bands of colour or moiré patterns.
HD. Hard drive (HDD). This is the internal, large-capacity storage unit in home computers, normally the C-Drive
Histogram. A histogram is a bar graph analysis tool that is used to identify contrast and dynamic range of any image. Histograms are found in the more advanced digi-cams and software programs (graphic editors), such as Adobe Photoshop 7, CS or Elements, and are used to manipulate images. The histogram shows a scale of 0 - 255 (left to right) with 0 being black and 255 being white.
Hot Shoe. A flash connector generally found on the top of the camera that lets you attach an external flash unit and trigger it in sync with the cameras shutter.
Hue. A term used to describe the complete range of colours of the spectrum. Hue is the component that determines just what colour you are using. In gradients where you use a colour model in which hue is a component, you can create some rainbow effects.
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i-TTL. Similar to Canon's "E-TTL", Nikon's new flash exposure system is used on the new D70 DSLR and SB-600 and SB-800 Speedlights.
Image Resolution. This relates to the number of pixels per unit length of image. E.g. pixels per inch, pixels per millimetre, or pixels wide etc..
Image Sensor. Digital cameras use an electronic image sensor (CCD or CMOS), to gather the image data, whereas a traditional camera exposes light to emulsion film,
Image Stabilization (IS). An optical or digital system built in to a lens for removing or reducing camera movement, most effective with telephoto or telephoto zoom lenses. Can be found on most of Canon's "L" range of lenses as well as mid-range lenses such as the EF 28-125 IS USM
Inkjet. A type of printer that "sprays" dots of ink onto paper to create the image rather than paint or laser it on. Modern inkjet printers now have resolutions of up to 2880dpi and create excellent photo quality prints.
Interlaced. This is the term used to describe an image sensor that gathers its data by first processing the odd lines, and then processing the even lines.
ISO. Or ASA. (International Standards Organization). The speed or light sensitivity of a captured image is rated by ISO numbers such as 100, 400, 800 etc. The higher the number, the more sensitive to light it is. Similar to film, the higher speeds usually bring on more electronic "noise" so the image gets grainier. An excellent program for cutting down this "noise" is Neat Image.
JPEG. Joint Photographic Experts Group. This is the name of the committee that designed the standard image compression algorithm. JPEG was designed for compressing full colour or grey scale digital images of natural scenes. It doesn't work so well with non-realistic images, such as cartoons however. JPEG does not handle the compression of black and white (1 bit-per-pixel) images or moving pictures.
Landscape Mode. This is when you hold the camera in its normal, horizontal orientation to capture the image. The opposite is "portrait mode".
LCD. (Liquid Crystal Display). There are 2 types. First, a TFT high-resolution colour display device like a very small TV set. Secondly, a monochrome (B and W) information display using just black alphanumeric characters on a grey or green background.
LED. (Light Emitting Diode). This refers to all the little red, green and yellow indicator lights used on most cameras, power supplies and electronic devices.
Li-ion. (Lithium ION). Some digicams are packaged with a lithium-ion re-chargeable battery pack. Lithium ION batteries are lighter but are more costly than Ni-MH or Ni-Cd (NiCad) rechargeables. One advantage is that Lithium cells can be recharged regardless of the amount of discharge; also, they are lighter and maintain a charge much better in colder temperatures than conventional batteries. Li-ion also holds a charge for longer when idle.
Lossless. Refers to storing an image in a non-compressed format, such as TIFF.
Mac. Refers to the Macintosh computers. I.e. Apple MAC. Macro. Lenses with this feature can focus very close (less than 8") for taking pictures of small objects at a 1:1 ratio.
Memory Stick. A flash memory card type from Sony. They resemble a stick of chewing gum and vary in size.
Memory Stick Pro. The year 2003 upgrade to Sony's Memory Stick flash cards. The new MS Pro cards are available in 256MB, 512MB and 1GB capacities and offer faster read/write times. All of Sony's digicams made in 2003 or after can use MS Pro cards.
Metering. Metering is used to calculate the exposure from the existing light conditions. Includes Matrix Metering, Spot metering and Center-weighted metering.
MOV. Apple QuickTime Movie file format.
Movie clip. A sequence of motion captured in AVI, MOV or MPEG formats. More and more digital cameras can now capture short movie clips, many can also record the sound.
Motion JPEG. A video clip composed of a sequence of JPEG compressed images. Sometimes abbreviated to MPEG (see MPEG below), although they are slightly different. The main difference is that MPEG provides temporal compression, while MJPEG simply provides spatial compression.
MPEG. Motion JPEG movie file. See "Movie clip"The digital video compression standard agreed upon by the Motion Picture Expert Group from the motion picture computer industry.
NEF. (Nikon Electronic Format). The Raw image data file format used by the Nikon DSLR (D2x, D100, etc) also some Coolpix digicams.
Noise. Relates to pixels in your image that were misinterpreted. Normally occurs when you shoot a long exposure (beyond 1/2-second) or when you use the higher ISO values from 400 or above. It appears as random groups of red, green or blue pixels. Programs such as Neat Image can remove most noise from an image.
Noise Reduction. Some cameras that offer long shutter speeds (more than 1 second) usually have a noise reduction (NR) feature that is either automatic or can be enabled in the menu. This is to help eliminate random "hot" pixels and other image noise. Can add a more time to the process as it needs to write the new image data along with the recorded image. Again, see Neat Image.
Optical Viewfinder. An eye level viewfinder that is used to compose the photograph.
Optical Zoom. Means that the camera has a real multi focal length lens, this is not the same as a "Digital Zoom" which magnifies the centre portion of the picture. Optical zoom gives better quality than a digital zoom.
Overexposure. This is an image that appears much too bright. The highlights and colours are totally lost and usually unrecoverable even by top software. Either the shutter speed was too long or the aperture was too wide.
Panorama. This means capturing a series of images to create a picture wider than what you could capture in a single image, by "Stitching" the photographs together. Needs special software to allow and help you do this.
Pixel. The individual imaging element of a CCD or CMOS sensor, or the individual output point of a display device. This is what is meant by the figures 640x480, 800x600, 1024x768, 1280x960 etc., when dealing with the resolution of a particular digicam. Higher numbers are best.
Pixelization. The stair stepped appearance of a curved or angled line in digital imaging. The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the image. Also known as the "jaggies".
Polarizer. (Polarising Filter). A filter for eliminating glare and reflections which attached to the front of your lens (normally just SLR's). Just like your polarized sunglasses it will get rid of glare, the polarizer filter does the same for your digicam. There are 2 types of polarising filter, linear and circular. Linear is for film only, it screws up most auto focus systems on digicams. Therefore be sure you use a circular polarizer filter. It can also be used to darken skies and increase the saturation of colours.
Point and Shoot. Term used for a simple, easy to use camera with a minimum of user controls. The camera does everything automatically so you literally just point and shoot.. PPI. Pixels Per Inch. A measurement to describe the size of a printed image. The higher the number the more detailed the print will be.
Rangefinder. This is the viewfinder on most smaller digital cameras and is a separate viewing device which is independent of the lens. It is often above and to the right or left of the lens. It exhibits a problem known as parallax when trying to frame subjects closer than five feet from the camera so it is advisable to use the colour LCD when shooting close-ups for just this reason.
RAW. RAW files store the unprocessed image data at 12 bits per channel. Directly from the camera's imaging chip to its memory storage device. "Lossless" compression is applied to reduce the file size slightly, without compromising the quality. RAW image files must be processed with special software before they can be viewed or printed. These are normally in the form of a plug in for Photoshop or as a standalone product. . The advantage is that you have the ability to alter the white balance, exposure value, colour values, contrast, brightness and sharpness as you see fit before you convert this data into the standard JPEG or TIFF format. Professional digital photographers import RAW image data directly into photo-editing programs like Photoshop CS (which comes with a Camera Raw plug-in that works with most popular RAW formats.)
Red-Eye. An effect caused by an electronic flash reflecting off the retina at the back of the eye making it look red. Compact cameras with the flash located close to the lens suffer the worst from this problem. Professional photographers use a bracket to hold an external flash unit above and off to the side of the lens to eliminate red-eye. It can also be easily reduced using most post-editing software.
Red-Eye Reduction Mode. A special flash mode whereby a pre flash or a series of low powered flashes are emitted before the main flash goes off. This causes the iris of the eye to contract meaning less light gets in the eye, therefore reducing red eye.
Render. This is the final step of an image transformation or three-dimensional scene through which a new image is refreshed on the screen.
Resize. In photographic terms, this means to take a large image and reduce it in size. Most editing programs offer a resize option. Good for cropping images or get them "Web-ready"!
Resolution. The quality of any digital image, whether printed or displayed on a screen, depends on its resolution, or the number of pixels used to create the image. More, smaller pixels add detail and sharpen the edges.
Saturation . The degree to which a colour is undiluted by white light. If a colour is 100 percent saturated, it contains no white light. If a colour has no saturation, it is a shade of grey.
Scanner. An optical device that converts images such as photographs, into digital form so that they can be stored and manipulated on your PC. Different methods of illumination transmit light through red, green and blue filters and digitize the image into a stream of pixels.
Scene Modes. Many digicams now have an exposure mode called scene where the user selects the best pre-programmed scene to suit the current shooting conditions. The camera will automatically change many settings to capture the best possible image. E.g. Sports, landscape, portrait etc.
SD. (Secure Digital). A flash memory card used in digicams and MP3 players. It is identical in size and shape to the MultiMedia Card (MMC). The difference being that SD cards were designed to hold protected (copyrighted) data like songs. Not all cameras that use SD cards can use MMC cards so be sure to read your owner manual before buying additional cards. Secure Digital. See "SD" above.
Self Timer. Preset time delay (e.g. 2, 5, 3, 5 or 10 seconds) before the shutter fires automatically. This allows the photographer be in the picture without using a long cable release or remote control. It is also great for taking macro or night shots as by not touching the camera, you eliminate the chances of camera shake. Is also good to use the "mirror lock up" function if you have it.
Sepia. The (brownish) mono toned effect seen in images from the original 19th and early 20th Century cameras. This is now a feature often found as a special image effect on some digicams and/or editing software.
Shutter. The physical device that opens and closes to let light from the scene strike the image sensor. Digicams use both electronic and mechanical shutters.
Shutter Lag. The time between pressing the shutter and actually capturing the image. This is due to the camera having to calculate the exposure, set the white balance and focus the lens. Is worse with smaller digicams whereas the better DSLR's now have little or no shutter lag, like the better film SLR's.
Shutter Priority AE. This is where the user chooses a shutter speed and the aperture is automatically determined by lighting conditions. Shutter speed priority is used to control motion capture. A fast shutter speed stops fast action, a slow shutter speed blurs a fast moving subject. It is good to use shutter priority for sports or wildlife photography.
Slow Sync. A flash mode in some digicams that opens the shutter for a longer than normal period and fires the flash just before it closes. Is used for illuminating a foreground subject, but allowing a darker background to also be well exposed. Good for night time shots of buildings with people in the foreground.
SLR. (Single Lens Reflex). This means the camera has a viewfinder that sees through the lens (TTL) by way of a 45°-angled mirror that flips up when the shutter fires and allows the light to strike the image sensor (or film). Basically, what you see is what you get.
SmartMedia. (SSFDC). A flash memory card that consists of a thin piece of plastic with laminated memory on the surface and uses a gold contact strip to connect to the camera. SmartMedia cards are available in various sizes.
Spot Metering. The camera's auto exposure system is focused on a very small area in the centre of the viewfinder to adjust the overall exposure value just for that area.
Telephoto . This is the focal length that gives you the narrowest angle of coverage, good for bringing distant objects closer. (i.e. 100mm, 200mm, 500mm etc.).TFT. (Thin Film Transistor). Refers to the type of hi-resolution, colour LCD screen used in digicams.
Thumbnail. A small, low resolution version of a larger image file, which is used for quick identification or speedy editing choices.
TIFF. (Tagged Image File Format). An uncompressed image file that is lossless and produces no artefacts as is common with other image formats such as JPEG.
Time-Lapse. Capturing a series of images at preset intervals. Also known as Interval Recording or Intervalometer.
Tran reflective. This is a type of LCD display that uses ambient light as well as a backlight to illuminate the pixels. It can be seen more easily in bright, outdoor conditions.
True Colour. Colour that has a depth of 24-bits per pixel and a total of 16.7 million colours.
TTL. (Through the Lens). Used when talking about either an auto focus or auto exposure system that works "through" the camera's lens.
Under exposure . A picture which appears too dark because insufficient light was delivered to the imaging system. Opposite of over exposure.
Unsharp Masking (Unsharp Mask). The process by which the apparent detail and sharpness of an image is increased. Generally accomplished by the input scanner or through computer manipulation using editing software.
USB. (Universal Serial Bus). This is the data I/O port on most digicams and is also found on modern home PC and Mac computers. It is faster than the serial port and transfers up to 12Mb/s (megabytes per second) with v1.1 interfaces.
USB 2.0. The newest USB standard which is close in throughput speed to FireWire, up to 400Mb/s.
UV Filter. This is an Ultra Violet absorbing filter that helps overcome the abundance of blue in outdoor photographs. Not really necessary in digital photography as the camera's white balance system adjusts for the colour temperature of the scene. Can be used to protect the camera's lens from scratching, fingerprints or dirt.
Viewfinder. The eye level device you look through to compose the image.
Vignetting. The term that describes the darkening of the outer edges of the image area due to the use of a filter or add-on lens. Most noticeable when the zoom lens is in full wide-angle. It is also sometimes used as a special effect in the photo editing stage of development.
This Digital Dictionary is on hand for whenever you come accross a photographic term you don't understand. Refer to it often and you will quickly master the "language" of digital photography, particularly useful when reading magazines or learning editing programs.
AC Power - Alternating Current which is used to operate your digital camera directly from the mains supply rather than a battery. Sometimes supplied, but normally requires additional expense.
AE - Auto Exposure. When the camera is set to this mode, it will automatically set all the required modes for the light conditions. I.e. Shutter speed, aperture and white balance. The 3 types are:
- Program Mode. The camera will choose the shutter speed and aperture automatically, effectively making your SLR a "point-and-shoot". It will normally assign a shutter speed of 60th of a second or higher if possible.
- Aperture Priority. You choose the aperture setting and the camera will automatically choose the shutter speed according to the lighting conditions. Best setting for controlling the depth of field.
- Shutter Priority. You choose the shutter speed and the camera will select the correct aperture as long as there is enough light. Good for sports or action photography where you need control over the shutter speeds.
AF. Auto Focus. All digicams and most modern SLR lenses have this function now. The lens automatically focuses on the subject as quick as the eye. The only difference is that with an SLR you can normally select manual focus if necessary.
Angle of View. This is calculated by the focal length of the lens and the size of the image sensor. The 35mm equivalents differ according to the sensor size.
Aperture. The lens opening that allows more, or less light onto the sensor formed by a diaphragm inside the actual lens.
Aperture Priority AE. When using this mode, the user selects the aperture giving control over the Depth of Field. A large aperture letting more light in gives a small depth of field, meaning not much will be in focus. Whereas a small aperture, not letting much light in, will give a greater depth of field or more will be in focus from the front to back of the image.
Aspherical Lens. A lens with edges flattened so that it is not a perfect sphere. These produce a much superior image.
Automatic Exposure. The camera sets the shutter speed and aperture for the correct exposure according to the light.
Automatic Focus. The lens on the camera focuses automatically when the shutter is half pressed. The viewfinder normally has focussing points shown to assist the user in knowing what will be in focus.
AVI. Movie clip in Windows AVI format. A lot of digicams now have this feature for producing small video clips.
AWB. Automatic White Balance. Most digital cameras have this feature where the camera sets the white balance. Override is available in most DSLR's.
B & W . Abbreviation for Black and White.
Back Lit. Meaning the subject is lit from behind which can cause underexposing. Is also used for portrait photography for special effects and bringing catchlights to the hair.
Backlight. The illumination for a colour LCD display on digital cameras or phones.
BMP. Bitmapped graphics file format which is popular with Windows PC's. It is an uncompressed file format like a TIFF.
Borderless. Quite simply, this means a printed photograph with no border around it.
Bracketing. Can apply to flash or exposure. It is used to create usually 3 photographs. One photo is exposed by the cameras meter automatically, one under exposed and one overexposed by a predetermined number of stops. Also "exposure bracketing".
Brightness. Value of a pixel in a digital image giving its value of lightness from black to white, with o being black and 255 being white.
Bulb. Term used for a long exposure setting normally more than 30 seconds. The start of the exposure is made by pressing the shutter, only ending when the shutter button is released. Excellent for night photography and a remote release is recommended to prevent camera shake as you press the shutter button.
Burst Mode. Also know as continuous mode or "Auto wind" on older SLR's. However, today's Digital SLR's have bust modes of up to 8 frames per second. Great for sports and action shots.
Calibration. The act of adjusting the colour of one device to match that of another. For example when you match the calibration of your screen to that of your printer to ensure what you see is what you print. It is also used in the film SLR's Canon EOS-3 and EOS 5 which have eye-controlled focussing. You calibrate the cameras focussing to where your eye is looking in the viewfinder. (Some fighter planes also have this. The missile follows the trajectory of the pilot's eye).
Card Reader. Used for transferring data from your flash memory card to your PC. A better way of transferring your image files than connecting the camera to your PC. Sometimes the cameras circuitry can become corrupt. Better to fry a memory card than your camera.
CF. Compact Flash card. Used in your digital camera to record images. Storage space ranges from 16MB up to 12GB. A company in Japan is currently developing a CF card that will store 2TB of information or 2,048 Gigabytes.
Chroma. The colour of an image element or pixel. A chroma is made up of saturation plus the hue values, but is separate from the luminance value.
Chromatic Aberration. Also known as purple fringing. It is fairly common in 2MP digital cameras and above, especially if they have long telephoto lenses. You can see it when a dark area is surrounded by a highlight. In between the dark and light, you may see a band of purple pixels that shouldn't be there. There are ways of removing this which I have covered in the Photoshop section.
CMYK. Cyan, Magenta, Yellow and BlacK. Colours used by most printers to produce your prints. Colour shifts can be caused when the colour management system tries to convert your PC's RGB files to CMYK. Before printing, try converting your images to CMYK and see what the difference is.
Colour Balance. The accuracy with which the colours captured in the image, match the original scene.
Colour Cast. This is a very unwanted tint of one colour in an image caused by the wrong amount of Cyan, Magenta and Yellow. It can be corrected using your editing software.
Colour Correction. To correct or enhance the colours within an image.
Colour Depth. Digital Images can approximate colour realism but the process is referred to as colour depth, bit depth or pixel depth. Most modern computer displays use 24 bit true colour. It displays the same number of colours that the human eye can discern, about 16 million.
Colour Space. Digital cameras use known colour profiles to generate their images. The most common is sRGB or Adobe RGB. This along with all of the other camera data is stored in the Exif header of the Jpeg file. The colour space information ensures that graphic programs and printers have a reference to the colour profile that the camera used at the time of taking the exposure.
Compact Flash. See CF. This is the most commonly used type of memory. It is small, removable and available in a wide range of sizes up to 12GB.
Continuous Autofocus. As it says. The auto focus system is continuously working on focussing on the subject.
Contrast. The measure of rate of change of brightness in an image.
Dark Frame. A noise reduction process where a camera takes a second exposure of a black frame after the camera takes a long exposure image. The image noise is easily identified in the black frame shot and is then electronically removed from the actual image. This helps to reduce the amount of hot pixels that normally show up in long exposure shots from digital cameras.
Dedicated Flash. An Electronic Flash Unit that is made to be used directly with a specific make or model of a camera. Canon, Nikon Minolta and Olympus for example, all have electrical contacts in the hotshoe which passes TTL (through the lens) metering and AF range information to and from the flash unit or speedlight. Youcannot interchange flash units and cameras. I.e. a Nikon speedlight on a Canon camera.
Depth of Field. (DOF). The range of items in focus in an image. This is controlled by the focal length and aperture opening of a lens. A large or wide aperture gives a shallow depth of field (not much range in focus) and a smaller or narrow aperture give a large depth of field (more range in focus).
Digital Film. Quite simply that. Solid state flash memory cards in place of emulsion film.
Digital Zoom. A digital magnification of the centre 50% of an image. These give less than sharp images because the new zoomed image has been interpolated. Don't be swayed by the incredible 500% zooms on some cameras, the images won't be really acceptable. The optical zoom gives much more clarity to an image.
DOF. Abbreviation of Depth of Field.
Download. Term used for the transference of image data from the camera to your computer. Can be done via a serial port or the faster USB port. Downloads can also be done via Bluetooth or Infra-red without the need for cables.
DPI. Dots per Inch. This is a measurement value used to describe the resolution of a display screen or that of a printer
DSLR. Digital Single Lens Reflex (SLR). Camera with interchangeable lens.
DVD. Digital Versatile Disk. DVD is DVD recorded on a DVD-R or DVD-RW disc.
Dynamic Range. This is a measurement of the accuracy of an image in colour or grey level. More bits of dynamic range results in much finer gradations being preserved.
EV. Exposure Value. The ability to override the auto exposure system to under or over expose the image.
Exposure. Amount of light that hits the image sensor of film controlled by the shutter speed and aperture.
Exposure Bracketing. Camera will take 3 or 5 images and varies the exposure up or down for each photograph ensuring at least one will be well exposed.
Exposure Compensation. You can lighten or darken the image by under or over exposing the image. (EV compensation).
F-Stop . Number indicating the size of the aperture. It is an inversely proportionate number as in F2.8 is a large opening and F16 is a small opening.
File. A collection of information like data, text or images which are saved on a CD. DVD or hard drive.
File Format. Type of program or data file. Includes JPEG, TIFF and BMP
Fill in Flash. See Fill in Flash
Fixed Aperture. Aperture remains constant regardless of the lens' focal length. I.e. The Canon "L" series have a constant fixed aperture when zooming.
Fixed Focal Length. Basically a non zoom lens. 100mm, 50mm, 200mm etc.
Flat Bed Scanner. Optical Scanner in which the original image remains stationary while the CCD sensors pass over or under it. The scanned image is held flat by the lid hence the name.
Focal Length. A lens' angle of view. Such as Wide angle, standard or telephoto.
Focus Lock. Focus lock means pre-focussing the subject and re-framing by moving the camera. This is done by half pressing the shutter to focus and fully pressing to expose. Done to ensure crisp, sharp eyes for example.
Frame. One of many still pictures that make up a video.
Frame Rate. Number of frames that are shown or sent each second. Live action is around 30 frames per second.
Gamma . Measure of the amount of contrast in an image according to the properties of a gradation curve. High contrast = High Gamma and Low = Low.
Gigabyte (GB). A gigabyte is a measure of computer memory or disk space consisting of about one billion bytes (a thousand megabytes). The actual value is 1,073,741,824 bytes (1024 megabytes).
Gradation. A smooth transition between black and white, one colour and another or colour and no colour.
Grey Level. This is the brightness level of a pixel representing it's lightness from black to white. It is usually defined as a value from 0 to 255, with 0 being black and 255 being white.
Grey Scale. A term used to describe an image containing shades of grey rather than colour. Most commonly referred to as a black and white photograph.
Halftone Image. An image reproduced through a special screen made up of dots of various sizes, to simulate shades of grey in an image. Normally used for magazine or newspaper reproduction of images. It is also how modern inkjet printers work. Half toning or dithering are the methods used to produce a smooth gradation of colour versus distinct bands of colour or moiré patterns.
HD. Hard drive (HDD). This is the internal, large-capacity storage unit in home computers, normally the C-Drive
Histogram. A histogram is a bar graph analysis tool that is used to identify contrast and dynamic range of any image. Histograms are found in the more advanced digi-cams and software programs (graphic editors), such as Adobe Photoshop 7, CS or Elements, and are used to manipulate images. The histogram shows a scale of 0 - 255 (left to right) with 0 being black and 255 being white.
Hot Shoe. A flash connector generally found on the top of the camera that lets you attach an external flash unit and trigger it in sync with the cameras shutter.
Hue. A term used to describe the complete range of colours of the spectrum. Hue is the component that determines just what colour you are using. In gradients where you use a colour model in which hue is a component, you can create some rainbow effects.
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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
i-TTL. Similar to Canon's "E-TTL", Nikon's new flash exposure system is used on the new D70 DSLR and SB-600 and SB-800 Speedlights.
Image Resolution. This relates to the number of pixels per unit length of image. E.g. pixels per inch, pixels per millimetre, or pixels wide etc..
Image Sensor. Digital cameras use an electronic image sensor (CCD or CMOS), to gather the image data, whereas a traditional camera exposes light to emulsion film,
Image Stabilization (IS). An optical or digital system built in to a lens for removing or reducing camera movement, most effective with telephoto or telephoto zoom lenses. Can be found on most of Canon's "L" range of lenses as well as mid-range lenses such as the EF 28-125 IS USM
Inkjet. A type of printer that "sprays" dots of ink onto paper to create the image rather than paint or laser it on. Modern inkjet printers now have resolutions of up to 2880dpi and create excellent photo quality prints.
Interlaced. This is the term used to describe an image sensor that gathers its data by first processing the odd lines, and then processing the even lines.
ISO. Or ASA. (International Standards Organization). The speed or light sensitivity of a captured image is rated by ISO numbers such as 100, 400, 800 etc. The higher the number, the more sensitive to light it is. Similar to film, the higher speeds usually bring on more electronic "noise" so the image gets grainier. An excellent program for cutting down this "noise" is Neat Image.
JPEG. Joint Photographic Experts Group. This is the name of the committee that designed the standard image compression algorithm. JPEG was designed for compressing full colour or grey scale digital images of natural scenes. It doesn't work so well with non-realistic images, such as cartoons however. JPEG does not handle the compression of black and white (1 bit-per-pixel) images or moving pictures.
Landscape Mode. This is when you hold the camera in its normal, horizontal orientation to capture the image. The opposite is "portrait mode".
LCD. (Liquid Crystal Display). There are 2 types. First, a TFT high-resolution colour display device like a very small TV set. Secondly, a monochrome (B and W) information display using just black alphanumeric characters on a grey or green background.
LED. (Light Emitting Diode). This refers to all the little red, green and yellow indicator lights used on most cameras, power supplies and electronic devices.
Li-ion. (Lithium ION). Some digicams are packaged with a lithium-ion re-chargeable battery pack. Lithium ION batteries are lighter but are more costly than Ni-MH or Ni-Cd (NiCad) rechargeables. One advantage is that Lithium cells can be recharged regardless of the amount of discharge; also, they are lighter and maintain a charge much better in colder temperatures than conventional batteries. Li-ion also holds a charge for longer when idle.
Lossless. Refers to storing an image in a non-compressed format, such as TIFF.
Mac. Refers to the Macintosh computers. I.e. Apple MAC. Macro. Lenses with this feature can focus very close (less than 8") for taking pictures of small objects at a 1:1 ratio.
Memory Stick. A flash memory card type from Sony. They resemble a stick of chewing gum and vary in size.
Memory Stick Pro. The year 2003 upgrade to Sony's Memory Stick flash cards. The new MS Pro cards are available in 256MB, 512MB and 1GB capacities and offer faster read/write times. All of Sony's digicams made in 2003 or after can use MS Pro cards.
Metering. Metering is used to calculate the exposure from the existing light conditions. Includes Matrix Metering, Spot metering and Center-weighted metering.
MOV. Apple QuickTime Movie file format.
Movie clip. A sequence of motion captured in AVI, MOV or MPEG formats. More and more digital cameras can now capture short movie clips, many can also record the sound.
Motion JPEG. A video clip composed of a sequence of JPEG compressed images. Sometimes abbreviated to MPEG (see MPEG below), although they are slightly different. The main difference is that MPEG provides temporal compression, while MJPEG simply provides spatial compression.
MPEG. Motion JPEG movie file. See "Movie clip"The digital video compression standard agreed upon by the Motion Picture Expert Group from the motion picture computer industry.
NEF. (Nikon Electronic Format). The Raw image data file format used by the Nikon DSLR (D2x, D100, etc) also some Coolpix digicams.
Noise. Relates to pixels in your image that were misinterpreted. Normally occurs when you shoot a long exposure (beyond 1/2-second) or when you use the higher ISO values from 400 or above. It appears as random groups of red, green or blue pixels. Programs such as Neat Image can remove most noise from an image.
Noise Reduction. Some cameras that offer long shutter speeds (more than 1 second) usually have a noise reduction (NR) feature that is either automatic or can be enabled in the menu. This is to help eliminate random "hot" pixels and other image noise. Can add a more time to the process as it needs to write the new image data along with the recorded image. Again, see Neat Image.
Optical Viewfinder. An eye level viewfinder that is used to compose the photograph.
Optical Zoom. Means that the camera has a real multi focal length lens, this is not the same as a "Digital Zoom" which magnifies the centre portion of the picture. Optical zoom gives better quality than a digital zoom.
Overexposure. This is an image that appears much too bright. The highlights and colours are totally lost and usually unrecoverable even by top software. Either the shutter speed was too long or the aperture was too wide.
Panorama. This means capturing a series of images to create a picture wider than what you could capture in a single image, by "Stitching" the photographs together. Needs special software to allow and help you do this.
Pixel. The individual imaging element of a CCD or CMOS sensor, or the individual output point of a display device. This is what is meant by the figures 640x480, 800x600, 1024x768, 1280x960 etc., when dealing with the resolution of a particular digicam. Higher numbers are best.
Pixelization. The stair stepped appearance of a curved or angled line in digital imaging. The smaller the pixels, and the greater their number, the less apparent the "pixelization" of the image. Also known as the "jaggies".
Polarizer. (Polarising Filter). A filter for eliminating glare and reflections which attached to the front of your lens (normally just SLR's). Just like your polarized sunglasses it will get rid of glare, the polarizer filter does the same for your digicam. There are 2 types of polarising filter, linear and circular. Linear is for film only, it screws up most auto focus systems on digicams. Therefore be sure you use a circular polarizer filter. It can also be used to darken skies and increase the saturation of colours.
Point and Shoot. Term used for a simple, easy to use camera with a minimum of user controls. The camera does everything automatically so you literally just point and shoot.. PPI. Pixels Per Inch. A measurement to describe the size of a printed image. The higher the number the more detailed the print will be.
Rangefinder. This is the viewfinder on most smaller digital cameras and is a separate viewing device which is independent of the lens. It is often above and to the right or left of the lens. It exhibits a problem known as parallax when trying to frame subjects closer than five feet from the camera so it is advisable to use the colour LCD when shooting close-ups for just this reason.
RAW. RAW files store the unprocessed image data at 12 bits per channel. Directly from the camera's imaging chip to its memory storage device. "Lossless" compression is applied to reduce the file size slightly, without compromising the quality. RAW image files must be processed with special software before they can be viewed or printed. These are normally in the form of a plug in for Photoshop or as a standalone product. . The advantage is that you have the ability to alter the white balance, exposure value, colour values, contrast, brightness and sharpness as you see fit before you convert this data into the standard JPEG or TIFF format. Professional digital photographers import RAW image data directly into photo-editing programs like Photoshop CS (which comes with a Camera Raw plug-in that works with most popular RAW formats.)
Red-Eye. An effect caused by an electronic flash reflecting off the retina at the back of the eye making it look red. Compact cameras with the flash located close to the lens suffer the worst from this problem. Professional photographers use a bracket to hold an external flash unit above and off to the side of the lens to eliminate red-eye. It can also be easily reduced using most post-editing software.
Red-Eye Reduction Mode. A special flash mode whereby a pre flash or a series of low powered flashes are emitted before the main flash goes off. This causes the iris of the eye to contract meaning less light gets in the eye, therefore reducing red eye.
Render. This is the final step of an image transformation or three-dimensional scene through which a new image is refreshed on the screen.
Resize. In photographic terms, this means to take a large image and reduce it in size. Most editing programs offer a resize option. Good for cropping images or get them "Web-ready"!
Resolution. The quality of any digital image, whether printed or displayed on a screen, depends on its resolution, or the number of pixels used to create the image. More, smaller pixels add detail and sharpen the edges.
- Optical Resolution is an absolute number that the camera's image sensor can physically record.
- Interpolated Resolution adds pixels to the image using complex software algorithms to determine what colour they should be. It is important to note that interpolation doesn't add any new information to the image - it just makes it bigger!
Saturation . The degree to which a colour is undiluted by white light. If a colour is 100 percent saturated, it contains no white light. If a colour has no saturation, it is a shade of grey.
Scanner. An optical device that converts images such as photographs, into digital form so that they can be stored and manipulated on your PC. Different methods of illumination transmit light through red, green and blue filters and digitize the image into a stream of pixels.
Scene Modes. Many digicams now have an exposure mode called scene where the user selects the best pre-programmed scene to suit the current shooting conditions. The camera will automatically change many settings to capture the best possible image. E.g. Sports, landscape, portrait etc.
SD. (Secure Digital). A flash memory card used in digicams and MP3 players. It is identical in size and shape to the MultiMedia Card (MMC). The difference being that SD cards were designed to hold protected (copyrighted) data like songs. Not all cameras that use SD cards can use MMC cards so be sure to read your owner manual before buying additional cards. Secure Digital. See "SD" above.
Self Timer. Preset time delay (e.g. 2, 5, 3, 5 or 10 seconds) before the shutter fires automatically. This allows the photographer be in the picture without using a long cable release or remote control. It is also great for taking macro or night shots as by not touching the camera, you eliminate the chances of camera shake. Is also good to use the "mirror lock up" function if you have it.
Sepia. The (brownish) mono toned effect seen in images from the original 19th and early 20th Century cameras. This is now a feature often found as a special image effect on some digicams and/or editing software.
Shutter. The physical device that opens and closes to let light from the scene strike the image sensor. Digicams use both electronic and mechanical shutters.
Shutter Lag. The time between pressing the shutter and actually capturing the image. This is due to the camera having to calculate the exposure, set the white balance and focus the lens. Is worse with smaller digicams whereas the better DSLR's now have little or no shutter lag, like the better film SLR's.
Shutter Priority AE. This is where the user chooses a shutter speed and the aperture is automatically determined by lighting conditions. Shutter speed priority is used to control motion capture. A fast shutter speed stops fast action, a slow shutter speed blurs a fast moving subject. It is good to use shutter priority for sports or wildlife photography.
Slow Sync. A flash mode in some digicams that opens the shutter for a longer than normal period and fires the flash just before it closes. Is used for illuminating a foreground subject, but allowing a darker background to also be well exposed. Good for night time shots of buildings with people in the foreground.
SLR. (Single Lens Reflex). This means the camera has a viewfinder that sees through the lens (TTL) by way of a 45°-angled mirror that flips up when the shutter fires and allows the light to strike the image sensor (or film). Basically, what you see is what you get.
SmartMedia. (SSFDC). A flash memory card that consists of a thin piece of plastic with laminated memory on the surface and uses a gold contact strip to connect to the camera. SmartMedia cards are available in various sizes.
Spot Metering. The camera's auto exposure system is focused on a very small area in the centre of the viewfinder to adjust the overall exposure value just for that area.
Telephoto . This is the focal length that gives you the narrowest angle of coverage, good for bringing distant objects closer. (i.e. 100mm, 200mm, 500mm etc.).TFT. (Thin Film Transistor). Refers to the type of hi-resolution, colour LCD screen used in digicams.
Thumbnail. A small, low resolution version of a larger image file, which is used for quick identification or speedy editing choices.
TIFF. (Tagged Image File Format). An uncompressed image file that is lossless and produces no artefacts as is common with other image formats such as JPEG.
Time-Lapse. Capturing a series of images at preset intervals. Also known as Interval Recording or Intervalometer.
Tran reflective. This is a type of LCD display that uses ambient light as well as a backlight to illuminate the pixels. It can be seen more easily in bright, outdoor conditions.
True Colour. Colour that has a depth of 24-bits per pixel and a total of 16.7 million colours.
TTL. (Through the Lens). Used when talking about either an auto focus or auto exposure system that works "through" the camera's lens.
Under exposure . A picture which appears too dark because insufficient light was delivered to the imaging system. Opposite of over exposure.
Unsharp Masking (Unsharp Mask). The process by which the apparent detail and sharpness of an image is increased. Generally accomplished by the input scanner or through computer manipulation using editing software.
USB. (Universal Serial Bus). This is the data I/O port on most digicams and is also found on modern home PC and Mac computers. It is faster than the serial port and transfers up to 12Mb/s (megabytes per second) with v1.1 interfaces.
USB 2.0. The newest USB standard which is close in throughput speed to FireWire, up to 400Mb/s.
UV Filter. This is an Ultra Violet absorbing filter that helps overcome the abundance of blue in outdoor photographs. Not really necessary in digital photography as the camera's white balance system adjusts for the colour temperature of the scene. Can be used to protect the camera's lens from scratching, fingerprints or dirt.
Viewfinder. The eye level device you look through to compose the image.
Vignetting. The term that describes the darkening of the outer edges of the image area due to the use of a filter or add-on lens. Most noticeable when the zoom lens is in full wide-angle. It is also sometimes used as a special effect in the photo editing stage of development.