Digital Photography Glossary
Photography has a language like any other profession, so here is our language.
Digital photography is a form of photography that uses an array of light sensitive sensors to capture the image focused by the lens, as opposed to an exposure on light sensitive film. The captured image is then stored as a digital file ready for digital processing (colour correction, sizing, cropping, etc.), viewing or printing.
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Aperture
A small, circular opening inside the lens that can change in diameter to control the amount of light reaching the camera's sensor as a picture is taken. The aperture diameter is expressed in f-stops; the lower the number, the larger the aperture. For instance, the aperture opening when set to f/2.8 is larger than at f/8. The aperture and shutter speed together control the total amount of light reaching the sensor. A larger aperture passes more light through to the sensor. Many cameras have an aperture priority mode that allows you to adjust the aperture to your own liking. See also shutter speed.
Barrel distortion
Image distortion produced when the position of the camera lens is at its widest angle. Lines you expect to appear perpendicular are not. It is most noticeable when you have a straight edge near the side of the frame, such as when taking a wide angle shot of a building. Barrel distortion causes the edges of an image to look curved or at a skewed angle. Most barrel distortion can be corrected using image editing software.
Bracketing
Take several shots of the same scene at different exposure settings to help ensure getting at least one well-exposed photo; bracket in difficult lighting situations. Some digital cameras have automatic bracketing (see exposure compensation).
Camera shake
Caused by even a slight movement of the camera as it records an image. Camera shake is the main cause of blurred images.
Compact digital camera
A digital camera that does not take interchangeable lenses (though some take converter lenses). Compact digital cameras range from simple point-and-shoot to ones with advanced settings and manual and semi-automatic control.
Continuous mode (Burst mode)
A camera mode that lets you take multiple photos in rapid sequence as you hold the shutter release button down. It is used to capture a series of images or to photograph a fast or unpredictably moving subject.
Converter lens
A lens that attaches to the front of a digital camera, usually requiring an adapter so it mounts correctly on the front of the camera.
Depth-of-field (DOF)
Refers to how much of a photo is in focus when the camera is focused on the main subject. Depth-of-field is controlled by a camera's aperture, in conjunction with the focal length of the lens. Deep (more) depth-of-field means that all or most of the picture is in focus from front to back. Shallow (less) depth-of-field means that a subject is in focus but objects in front and behind it appear out of focus.
Digital zoom
A simulated zoom. The physical length of the lens does not change. The camera pre-crops the central portion of an image and reduces its resolution giving an appearance of zooming in. Image quality is degraded and contains increased noise (see optical zoom).
Dynamic range
The range of tones in a digital photo, from lightest to darkest. The greater the dynamic range, the more detail appears in both shadow and highlight areas. Generally, a DSLR has more dynamic range than a compact digital camera.
EXIF
Exchangeable Image File - Data that is stored in jpeg and TIFF image files, such as shutter speed, date and time, focal length, exposure compensation, metering pattern and if a flash was used a the time a photo was taken. EXIF data can be read by applications which support JPEG including web browsers, image editing programs and some printer software drivers
Exposure compensation
Increase or decrease the exposure an image from the exposure automatically selected by a camera metering system (see bracketing).
Exposure meter
Built-in digital camera meter that measures the amount of light when framing a photo and determines the best exposure. Matrix (Evaluative), Spot and Center-weighted are the main metering types; some digital cameras have all three.
Exposure values (EV)
Exposure Values are numbers that refer to various combinations of lens aperture and shutter speed. When bracketing a photo, decrease the EV if a scene will appear too light (over-exposed). Increase the value if a scene will look too dark (under-exposed).
Fill-in flash
Forces a flash to go off even in bright light; often used outside to soften dark areas or shadows. The camera will expose for the background first, then add enough fill-flash to illuminate your subject. Fill-in flash is also known as forced flash or flash on.
Flash exposure compensation
Digital camera control that lets you adjust the amount of output from the flash. Increase or decrease the amount to lighten or darken the effect of the flash.
FPS
Frames per second - the rate a digital camera or camcorder produce still images one right after another.
ISO (Sensitivity)
The number indicating the camera sensors sensitivity to light. The higher the sensitivity, the less light is needed to make an exposure (see noise).
Liquid Crystal Display (LCD)
Monitor on back of a digital camera that shows 100% of the view through the camera lens. Like a viewfinder, it can be used to preview a scene before taking a photo. The LCD also displays camera settings and can be used to review photos and videos saved to a memory card.
Megapixel
A megapixel is equal to one million pixels (picture elements). Digital images are made up of thousands of these tiny, tile-like picture elements.
Metering system
Measures the amount of light when framing a photo and determines the best exposure. The main digital camera metering types are: Matrix (Evaluative), Spot and Center-weighted.
Noise
Randomly-spaced speckles (pixels) that can appear in digital images shot at high ISO numbers. Noise results in a reduction of photo detail and clarity, though it can be reduced with special noise reduction software. Noise is most visible when photos are shot at ISO 200 and above with a consumer digital camera. Some digital cameras have a Super CCD where photos taken at higher ISO numbers (eg. ISO 1600) have little, if any, visible noise.
Optical zoom
A true zoom. The focal length of the lens extends and retracts so an image is magnified by the lens itself. Whatever the focal length of the lens, image resolution stays the same. Optical zooms produce the best photo quality (see digital zoom)
Overexposure
Improper exposure causing an image to look too light. There is a loss of detail in bright areas.
PictBridge
A standardized technology that lets you print images from a memory card in a digital camera directly to a printer regardless of brand. No computer is necessary.
Saturation
The intensity, or vividness, of a color. Increasing saturation makes colors in photos look richer. The amount of saturation can be adjusted in some cameras. It can also be increased or decreased with image editing software.
Shutter lag
The delay that takes place between pressing the shutter-release button and the time a photo is actually taken. Shutter lag times vary from digital camera to digital camera.
Shutter-release button
the shutter-release button on a digital camera must be pressed in two steps to lock exposure and focus and to help prevent camera shake
Sunny 16 rule
The “Sunny 16” rule suggests that on a sunny day, you manually set your aperture to f16 and your shutter speed to the reciprocal of your ISO value. This can improve exposure and help prevent clipped highlights.
Underexposure
Improper exposure causing an image to look too dark. There is a loss of detail in dark areas.
White balance
Adjusts the brightest part of a scene so it appears white. How a digital camera records color is affected by the source of light
