Glossary

This is a growing glossary of common camera terms. Feel free to add items that aren't listed.

• 35mm - A film format with frames measuring 24mm x 36mm on a roll of film wound into an easy-to-load cassette.
• aperture - An opening in a lens that limits the amount of light passing through it.
• aperture priority
• autofocus
• auto exposure
• center-weighted
• coupled rangefinder - A rangefinder that provides a focusing aid which is "coupled" to the focus adjustment on a lens.
• depth of field - The range of distances (from near to far) within which a scene will be considered to be "in focus."
• diopter - An optical adjustment that allows someone to adjust the viewfinder's magnification to their vision.
• f-stop - The measure of the aperture setting on a lens.
• field of view - The diagonal measure of the part of a scene that is visible with a given lens.
• film advance
• flash sync - The manner by which a flash is fired while the shutter is open.
• focal plane - The flat plane onto which a lens focuses its image.
• large format - A film format larger than medium format, in which negatives are loaded one at a time rather than in rolls.
• leaf shutter
• lens - One or more glass elements used to focus an image onto the focal plane.
• light meter - A device that measures light to determine the proper exposure settings for a scene.
• medium format - A film format larger than 35mm but smaller than large format (typically 120 film) wound onto spools.
• mirror lockup - A feature on some SLRs that allows the reflex mirror to be locked in the up position to eliminate vibration.
• optical axis - The straight line which passes through the centers of curvature of the lens surfaces.
• parallax - An effect in photography where the image seen in the viewfinder is not the same as the image seen through the lens.
• point-and-shoot - Camera designed to eliminate the user's need to make focus and exposure settings.
• QL - A Canon designation for film cameras using their "quick loading" feature.
• rangefinder base - A measure of distance between the viewfinder and rangefinder windows on a rangefinder camera.
• rear-curtain sync
• shutter curtain
• shutter release - The mechanism (usually a button) that causes the shutter to open and close.
• SLR - "Single Lens Reflex."
• TLR - "Twin Lens Reflex."
• toy camera - An inexpensive camera usually made almost entirely out of plastic.
• TTL - "Through the Lens."
• viewfinder - The part of a camera you look through when composing your shot.