Glossary of Photographic Terms


I remember spending a week during my college years studying flash cards for over a thousand vocabulary words. Although I was an English major and had loved reading, I had never really took it upon myself to learn the definitions of the hard words.
Finally motivated by an entrance exam for grad school, I discovered to my amazement that learning the actual definitions of words made reading the classics much more enjoyable. Go figure... If only I had come to this realization in high school. The truth is that knowing what each term means - whether it be technical or Shakespearean - makes the practice of any art or science more enjoyable. Who likes to constantly turn to a dictionary? That's why I recommend taking these terms to heart - memorizing them in any manner that works for you - so you can more rapidly excel as a photographer.

Note: Also check out these free resources at BetterPhoto.com:

         
The Top Ten Vocabulary Words
The American Heritage Dictionary defines photography as "the art, practice, or occupation of taking and printing photographs." If that is all you need to hear, feel free to move on learning technique. If, on the other hand, that still leaves things a little vague for you… onward, forward, dear reader.
The following are the most important definitions; learn these terms to become a better photographer regardless of your specialty. Roll over each word with your mouse and hold it there for few seconds to be given a hint. Click on the word to read an extended definition.
 
 
Photography
 
SLR
 
 
 
Rule of Thirds
 
Golden Rectangle
 
 
 
Shutter Speed
 
Aperture
 
 
 
Digital Imaging
 
Depth of Field
 
 
 
Focal Length
 
Sunny-16 Rule
 
 
The Full Meal Deal
This second section consists of the extended definitions of just about every word you may have ever heard that relates to photography.
 
AE
Automatic Exposure; Three kinds are available: programmed auto exposure, aperture-priority auto exposure and shutter-priority auto exposure.
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AE Lock
Used to hold an automatically controlled shutter speed and/or lens aperture, in case you need to recompose your picture but want to retain an previous exposure reading.
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AF-I (Nikon)
Lens with built-in autofocus drive motor. CPU is also built in. AF-I Nikkor lenses send information on distance to the camera body and are classified as D-type AF Nikkor lenses.
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AI (Nikon)
Automatic index; Nikon's system for telling the camera's exposure meter what the lens' maximum aperture is.
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AI/S (Nikon)
Automatic index/Shutter; Nikon's lens mount permitting automatic operation in shutter-priority and program auto-exposure systems.
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Aperture
The variable opening produced by the iris-diaphragm through which light passes to the film plane. Measured in f/stops.
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Aperture Priority
Autoexposure systems wherein the photographer selects the aperture and the camera selects the appropriate shutter speed.
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APO
Apochromatic; a type of lens which focuses different wavelengths of light on the filmplane for improved image sharpness. Especially useful in telephoto lenses. (Chromatic aberration is corrected).
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ASA
American Standards Association; (see ISO).
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B (Bulb)
At the B setting, the shutter remains open as long as the shutter release button remains fully depressed.
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Bracketing
Take a series of pictures at different exposures.
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Coating
A layer or multiple layers of thin anti-reflective materials applied to the surface of lens elements to reduce light reflection (flare) and increase the amount of transmitted light.
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Close-Up
The general term for pictures taken at relatively close distances, from 1/10 life-size (1:10) to life-size (1:1).
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Depth of Field
The range of acceptably sharp focus in front of and behind the distance the lens is focused on.
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Diaphragm
A series of metal "blades" that can be manipulated to form a larger or smaller opening through which the light is admitted.
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Digital Imaging
The new evolution of the art of photography where images are scanned into an electronic format and then "processed" with software such as Adobe Photoshop.
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DX-Coding
Code printed on film cartridges providing most new cameras with film speed information.
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Element
One piece of glass comprising the internal optics of a lens. (See Group).
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EOS (Canon)
Electronic Optical System; Canon's current line of autofocus cameras and accessories.
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E-TTL (Canon)
Evaluative, through-the-lens flash metering.
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EV
Exposure Value; A number that represents available combinations of shutter speed and aperture offering the same exposure effect when scene brightness remains the same. Each EV number can be applied to various shutter speed and aperture combinations.
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Exposure
Light striking a sensitized material (film or paper emulsion).
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Exposure Compensation
Modifying the shutter speed and/or lens aperture recommended by the camera's light meter in order to produce special creative effects or to meet special requirements.
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Fill-Flash
Exposure consisting of a combination of flash and "available light" balanced to produce a pleasing mix of the two.
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Fisheye
An ultra-wide angle lens which purposely introduces barrel distortion so straight lines near the edges of the frame appear to curve out.
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Flare
Image degradation caused by stray light which passes through the lens but is not focused to form the primary image. Often caused by light bouncing off internal air-to-glass surfaces.
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Focal Length
The distance from the optical center of a lens to the image plane when the lens is focused to infinity.
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Golden Rectangle
An image ratio (width vs the height) that makes the most pleasing, balanced impression on the viewer. Panoramics are long and skinny; square negatives often make it hard for the viewer to recognize the central focus of a composition. A 35mm format is pretty close to a golden retangle.
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Group
Two or more elements cemented together within a lens. Lenses are described as having a certain number of elements in a certain smaller number of groups.
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Guide Number
The power of a flash in relation to ISO film speed. Guide numbers are quoted in either meters or feet. (To convert from meters to feet, multiply the metric number by 3.3). Guide numbers are used to calculate the f/stop for correct exposure as follows: f/stop=guide number/distance.
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Hot Shoe
A mounting device, usually built onto the top of a camera, that enables a flash unit, or speedlight, to be mounted on and triggered by the camera.
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ISO
International Standards Organization; the number represents the film's sensitivity to light. A higher ISO number indicates the film is more sensitive and requires less light for a proper exposure.
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Latitude
The variance from "proper" exposure which will still provide acceptable results.
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Matrix
Autoexposure metering where the camera sets both aperture and shutter speed according to data stored in the camera's built-in memory, comparing the scene to be photographed to reference scenes.
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Macro Focusing
Macro focusing, applied to zoom lenses, moves the lens group(s), enabling the lens to focus closer than the normal focusing distance from close-up shooting.
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Photography
From the Greek the means "painting or writing with light."
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Resolution
A word with many meanings. In digital imaging, it most often refers to the number of pixels per inch in an image file. It can also refer to printer resolution, digital camera CCD resolution, etc. In traditional photography, if refers to the ability of a lens or photographic material to reproduce small details and is measured in lines per millimeter.
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Shutter Speed
How fast the camera's shutters open. Determines how long the film is exposed for.
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Shutter Priority
When the photographer selects the shutter speed and the camera automatically sets the corresponding aperture.
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SLR
Single Lens Reflex; a camera with one lens (as opposed to Twin Lens Reflex like the Rolleiflex) that involves a mirror and prism that the viewer looks through (as opposed to a point and shoot or rangefinder where the viewer looks through a separate viewfinder.
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Sunny-16 Rule
A guideline that states that you can expose a normal scene, lit by bright sunlight, at an aperture of f16 and a shutter speed equivalent to the film speed (ISO or ASA) being used.
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TTL
Through-the-lens; commonly used when referring to metering through the lens as opposed to via a separate meter. Effective for fill-flash and other tricky lighting situations
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Rule of Thirds
See the Top Ten Tips.
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USM (Canon)
UltraSonic Motor; Canon's fastest, quietest autofocus lens mechanism.
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