• APERTURE: an opening in the lens that changes in size to control the AMOUNT of light passing through the lens of the camera.
  
  
• APERTURE PRIORITY MODE: an automatic camera mode where you set the camera's aperture and the meter will set the shutter speed for correct exposure.
  
  
• DEPTH OF FIELD: the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.
  
  
• F-STOP: A fraction that measures of the size of the aperture opening on a camera.
  
  
• IRIS: The part of a lens mechanism that can expand and contract to control the amount of light passing through a lens.
  
  
• ISO: A system used to measure and adjust how sensitive a digital camera is to light.
  
  
• RECIPROCITY: when you ADD a "stop" of light entering the camera with one of the camera exposure controls (i.e. shutter), then BALANCE it by taking AWAY a "stop" of light with the other (i.e. aperture)
  
  
• SHUTTER: The device on a camera that opens and allows light to pass to the sensor or film for a set period of time in order make an exposure.
  
  
• SHUTTER SPEED: the length of time a shutter remains open as measured in seconds or fractions of a second.
  
  
• SHUTTER PRIORITY MODE: A camera shooting mode that lets the photographer define the camera's shutter speed and the camera will then set the aperture for a correct exposure based on its light metering.
  
  
• EXPOSURE BRACKET: a technique of taking several shots of a scene using different camera settings to ensure getting a good image

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