D & R Camera House Esperance Western Australia. Glossary of Terms.

Glossary of Camera & Photography Terms

Adaptor lens: An add-on lens that changes the focusing capabilities of the camera's lens. Wide-angle, telephoto and close-up lenses are available for some cameras (normally the higher-priced models).
Aperture: The adjustable hole in the lens assembly that lets in the light. The larger the aperture, the more light it lets in. However, because the aperture value represents a ratio of the lens focal length to the diameter of the hole, large apertures are denoted by small f-numbers (f2.8 is a common maximum aperture for a digital camera).
Aperture Priority: A camera control that lets the photographer set the aperture value and have the shutter speed determined by the camera's auto exposure system.
Aspect Ratio: The relationship between the horizontal and vertical dimensions of an image. A 35mm film frame has an aspect ratio of 3:2 (which is the same as a standard 10 x 15cm print). Most digital cameras produce images with a 4:3 aspect ratio.
A/V Cable: The cable used for connecting a digital camera to a TV set for playback.
Autofocus (AF): A camera control that focuses the lens on the subject. Two types of AF are in common use, infrared (IR) and contrast-based. The former fires a beam of infrared light at the subject and calculates its distance on the basis of the return reflection, while the latter evaluates distance on the basis of image contrast (close subjects have higher contrast than their background).
Backlighting: Light that comes mainly from behind the subject.
Batteries: Digital Cameras rely on battery power. Some use rechargeable lithium ion batteries; others use common AA or AAA cells, but will generally accept both rechargeable NiMH and non-rechargeable alkaline types.
Buffer Memory: A special RAM storage area in a digital camera's memory system where image data is held while it awaits processing and transfer to the camera's memory card. A large buffer memory is required to support high-speed continuous shooting, especially at high image resolution.
Burst (Continuous) Shooting: A function that allows a camera to capture a number of sequential shots in rapid succession. The number of frames that can be captured depends on the image resolution and the size of the buffer memory.
CCD (Charge-Coupled Device): A light-sensitive array of silicon cells that is commonly used for digital camera image sensors. It generates electrical current in proportion to light input and allows the simultaneous capture of many pixels with one brief exposure.
Colour Saturation: The intensity of a hue. Pastels have low saturation, while bright colours are highly-saturated.
Composition Aids: Visual guides, such as sample pictures or on-screen gridlines, that help you to compose your photos more effectively.
Compression: A mathematical processing system used to reduce the size of digital data files. Two types of compression are common in digital photography: lossy (which sacrifices some data in order to obtain small files) and lossless (which involves little or no information loss).
Continuous Shooting: See Burst Shooting.
Contrast: The range of tones between the brightest and darkest areas in a subject or picture. Low contrast subjects have a very wide range of tones, while high contrast subjects have fewer distinct tones.
Cropping: Cutting out a subsection of an image, discarding the rest, to improve the picture.
DCIM: A root level folder in a digital camera or on a personal computer in which image data from a digital camera is stored. Each time you turn on the camera or insert a different card, any empty folders within the DCIM folder are removed. New folders are created automatically in the computer with each set of image downloads.
Depth of Field: The range of focus within a scene. A large depth of field means that objects both near and far from the camera will all be in focus.
Digital Memory Cards: Digital cameras use memory cards instead of traditional negative film to store images. The cards are available in various storage sizes from 16 Mb to 1 Gb. The number of images each card holds is dependant on the resolution quality you select . . . good, better, best. The higher the resolution the less images the card can store.
Digital Zoom: A zoom effect created by enlarging the central portion of the image. Most cameras interpolate the captured data up to the selected camera resolution but this involves some loss of image quality.
Direct Print: A printer-based facility that allows shots from a camera or memory card to be printed directly, without the need for a computer.
Docking Station: A plug-in device that remains connected to a computer and allows files to be downloaded directly from a camera. Most docks also recharge the camera's battery.
Effective Pixels: The number of pixels that are actually used to capture the image (as distinct from the total pixel count for the sensor).
Electronic Viewfinder: A miniaturised screen that replicates the live image that would appear on the LCD monitor (and be captured by the camera's sensor).
Establishing Shots: Video clips that set the scene for the action shots to follow.
Exposure: The degree to which the film or CCD is exposed to the light when you take a picture. This depends on the aperture and the time the shutter is open.
Exposure Bracketing: Taking a series of shots of the same subject with different exposure levels that span across the metered exposure. This function is used to obtain a correctly exposed picture in difficult lighting conditions.
Exposure Compensation: A control that overrides the camera's metering system and allows you to adjust the exposure value. Most cameras offer a range of +2 to -2 EV of adjustment.
Flash: A very bright light that can illuminate a scene when you take a picture in conditions where there wouldn't normally be enough light.
Focus: By adjusting the distance between the various lenses within a camera, you can make objects sharp (in focus) or blurry (out of focus).
Focus Assist Light: A built-in illuminator that shines in dimly lit situations to help the camera's autofocusing system achieve sharp focus.
High Resolution images - above 1280 x 1024 pixels: When it comes to printing your images, especially on a large scale, you'll need to use the highest resolution your camera has to offer. While you may only be able to store a few of these mammoth-sized files on a RAM card, their detail levels are very high.
Histogram: A graph that shows the amount of red, green and blue colour within an image.
Index: A term normally used to denote multiple images on a viewing screen or print. Most cameras can present four, nine or 16 thumbnail images simultaneously.
Infrared: Light that is outside of the visible spectrum, used by some digital devices to communicate with each other without the need for cables running between them.
Interpolation: A mathematical resampling technique that is used to increase the size of an image file by creating more pixels on the basis of existing pixel values. Some quality is sacrificed, particularly when files are made larger.
ISP: Internet Service Provider - the company that supports your internet connection.
JPEG: The image file format developed by the Joint Photographic Experts Group and denoted by the '.jpg' extension. JPEG uses compression algorithms to reduce file sizes, sacrificing some image data to obtain small files.
Landscape Button: A dedicated button that automatically sets the camera's focus to infinity and switches off the flash to provide the optimum settings for scenic shots.
Landscape Format: A camera position or print orientation that presents the image with greater horizontal than vertical dimensions.
LCD: Liquid Crystal Display, a small low power display on some digital cameras, used to preview or review the images you take.
LCD Monitor: The display screen used to preview and review shots, and provide access to the camera's menu controls.
Lens: A piece of shaped glass that focuses light onto the film or CCD inside your camera.
Low Resolution images - below 800 x 600 pixels: Web pages, in particular, generally consist of images smaller than 640 x 480, making this resolution ideal for pictures destined for the Internet. The main drawback with these images is that if you intend to print them out they will appear fairly small, unless you stretch them, which makes them appear very blocky. You're also not going to capture any fine detail in your image.
Macro Mode: Allows a camera to focus on an object that is only a few centimetres away from the lens.
Medium Resolution images - 800 x 600 - 1280 x 1024 pixels: Images in this range take up more memory, take longer to process but reward you with much higher levels of detail and more flexibility in terms of what you can do with them.
Megapixel: A megapixel is one million pixels.
Memory Card: A removable solid state card on which digital cameras can store pictures.
Metering: The light measuring system that determines the appropriate exposure.
Multi-shot mode: A continuous shooting option that causes the camera to take a sequence of shots of a subject. Some cameras only save a few of these shots, allowing you to select the best one(s) to keep.
Night Portrait mode: A flash mode that combines a flash exposure with a slow shutter speed. This allows you to capture some background details that would otherwise be lost with a standard flash shot.
NTSC: The video format used in Japan and North America.
OLED: A new viewing screen technology that provides a wider viewing angle, better colour fidelity and lower power consumption than standard LCD screens.
Optical Viewfinder: A lens-based window that you look through to compose a photo.
Optical Zoom: Digital zoom features on digital cameras merely enlarge a cropped area of pixes to simulate the effect of a telephoto lens. An optical zoom works by physically adjusting the distance between the lenses within the camera. No picture quality is sacrificed in this process.
Panorama: A wide-angle picture either taken using a special lens or built up by joining several images together in an image editing program.
RAM: Random Access Memory - allows digital devices to store information temporarily.
Red-Eye: The optical effect in which eyes glow bright red in an image, is caused by light from the camera's flash reflecting off the retina at the back of the eye.
Resolution: The size of an image measured in pixels.
Serial Link: A basic means of connecting devices to your computer. Well supported, but now increasingly superceded by USB.
Shutter: The part of a camera that opens briefly to allow light to reach the film or CCD.
Shutter Speed: The length of time for which the camera's shutter stays open when taking a picture.
USB: Universal Serial Bus. A recent and very fast, option for linking digital cameras, scanners, and a wide range of other devices to your computer, allowing the rapid transfer of information between them.
Viewfinder: Eyepiece that allows you to frame your picture by showing you what the camera's lens will see when you press the shutter release button.
Zoom: The effect of moving closer to your subject achieved by adjusting the distance between lenses inside your camera.