A Glossary of Photographic Terms
Aperture
Lens opening. The opening in a camera lens through which light passes to expose the film. The size of aperture is either fixed or adjustable. Aperture size is usually calibrated in f-numbers-the larger the number, the smaller the lens opening.
Aperture Priority
An exposure mode on an automatic or autofocus camera that lets you set the aperture while the camera sets the shutter speed for proper exposure. If you change the aperture, or the light level changes, the shutter speed changes automatically.
Autofocus (AF)
System by which the camera lens automatically focuses the image of a selected part of the picture subject.
B (Bulb) Setting
A shutter-speed setting on an adjustable camera that allows for time exposures. When set on B, the shutter will stay open as long as the shutter release button remains depressed.
Bracketing
Taking additional pictures of the subject through a range of exposures-both lighter and darker-when unsure of the correct exposure.
Composition
The pleasing arrangement of the elements within a scene-the main subject, the foreground and background, and supporting subjects.
Depth of Field
The amount of distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. Depth of field depends on the lens opening, the focal length of the lens, and the distance from the lens to the subject.
Exposure
The quantity of light allowed to act on a photographic material; a product of the intensity (controlled by the lens opening) and the duration (controlled by the shutter speed or enlarging time) of light striking the film or paper.
Exposure Meter
An instrument with a light-sensitive cell that measures the light reflected from or falling on a subject, used as an aid for selecting the exposure setting. The same as a light meter.
f-Number
A number that indicates the size of the lens opening on an adjustable camera. The common f-numbers are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22. The larger the f-number, the smaller the lens opening. In this series, f/1.4 is the largest lens opening and f/22 is the smallest. Also called f-stops, they work in conjunction with shutter speeds to indicate exposure settings.
Focus
Adjustment of the distance setting on a lens to define the subject sharply
Lens Speed
The largest lens opening (smallest f-number) at which a lens can be set. A fast lens transmits more light and has a larger opening than a slow lens.
Macro Lens
A lens that provides continuous focusing from infinity to extreme close-ups, often to a reproduction ratio of 1:2 (half life-size) or 1:1 (life-size).
Panning
Moving the camera so that the image of a moving object remains in the same relative position in the viewfinder as you take a picture.
Polarizing Screen (Filter)
A filter that transmits light traveling in one plane while absorbing light traveling in other planes. When placed on a camera lens or on light sources, it can eliminate undesirable reflections from a subject such as water, glass, or other objects with shiny surfaces. This filter also darkens blue sky.
Project365
A project in which someone takes a photo a day for an entire year. Reasons are varied as to why you would take a photo a year. Some people participate in Project365 to document their life for an entire year while others participate in Project365 to become better photographers.
Shutter Priority
An exposure mode on an automatic or autofocus camera that lets you select the desired shutter speed; the camera sets the aperture for proper exposure. If you change the shutter speed, or the light level changes, the camera adjusts the aperture automatically.
Single-Lens-Reflex (SLR) Camera
A camera in which you view the scene through the same lens that takes the picture.
Telephoto Lens
A lens that makes a subject appear larger on film than does a normal lens at the same camera-to-subject distance. A telephoto lens has a longer focal length and narrower field of view than a normal lens.
Tripod
A three-legged supporting stand used to hold the camera steady. Especially useful when using slow shutter speeds and/or telephoto lenses.
Wide-Angle Lens
A lens that has a shorter focal length and a wider field of view (includes more subject area) than a normal lens.
Zoom Lens
A lens in which you adjust the focal length over a wide range. In effect, this gives you lenses of many focal lengths.