A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0-9


Ambient Light – Also referred to as available or existing light, it is the light surrounding a subject that has not been supplied by the photographer.  i.e. no flashes or studio lighting, just the light that the subject has normally – be it natural or artificial.

Analogous – Two or more colors on a color wheel that are next to or adjacent to each other.

Angle of View – The area of a scene that a lens covers or sees.  The angle of view is determined by the focal length of the lens you are using.  For example, a wide angel lens is going to cover a wider area of the scene than would a telephoto lens.

ApertureThe opening in the lens that allows light to pass through to the film or digital sensor.  A diaphragm inside the lens opens and closes its overlapping leaves to adjust the size of the aperture.  Aperture size is noted in f-numbers or f-stops.  The larger the f-number the smaller the opening and the smaller the f-number, the larger the opening.

Aperture PriorityOne of the exposure modes on a DSLR or SLR camera that allows the user to set the aperture while the camera sets the shutter speed to get the proper exposure.

Aspect Ratio – The ratio of width to height in a photo print.  Most commonly 2:3 or 4 x 6 for 35 mm film photography.

Auto Exposure (AE) – An exposure mode on camera that automatically sets the aperture and shutter speed to get the best exposure based on the available light and ISO.

Auto Focus (AF) – A feature on the camera that allows the lens to electronically set the correct focus of the subject.  In most cameras this is done by pressing the shutter release down half-way.

Auto Mode – A setting on the camera that allows the camera to determine the appropriate settings to obtain the best exposure of the image.  Can also be known as Auto Exposure.


Back Lighting – A light source coming from behind the subject and towards the camera lens.  Although difficult to manage sometimes back lighting can enhance an image.  Using a lens hood and the appropriate aperture will help.

Bokeh – The out of focus regions of an image usually deliberate to produce an artistic effect or draw attention to a specific area of the photograph.

Bracket(ing) – Taking a series of photographs of the same subject at different exposures to insure the “correct” exposure.  Usually involves taking one photograph and then taking the same shot with the aperture or shutter speed adjusted both up and down one stop.  For example shot 1 = f/8 and 1/200th of a second, shot 2 = f/5.6 and 1/200th of a second, and shot 3 = f/11 and 1/200th of a second.  Many modern DSLR cameras have automatic bracketing features.

Bulb Mode – a shutter speed setting that allows the shutter to remain open as long as the shutter release is held down.  Used for very long exposures this option is best done with a cable release to avoid camera shake.


Cable Release – A flexible cable that attaches to the camera and used to trigger the shutter without actually touching the camera.  It is particularly useful for slow shutter speeds and long time exposures, when touching the camera may cause camera shake that could result in blurring of the image.

Camera Shake – Movement of the camera due to an unsteady hand or camera support.  The result is a blurred image.  Many modern cameras has image stabilizers built into the camera itself or the lenses to help offset camera shake.

Center Weighted Metering – An auto exposure (AE) system found in some cameras that uses the center portion of the image to determine and adjust the overall exposure value.

CMYK – Stands for cyan, magenta, yellow and black and refers to the subtractive color model used in color printing.

Color Wheel – An illustrative representation of color hues, usually in a circle, that shows the relationship of colors to each other. Colors opposite each other on the wheel are complementary while those adjacent to each other are analogous.

Compact Flash – Digital image mass storage technology using flash memory in a small card.  It is the most common image storage for DSLR cameras today.

Complementary Colors – Pairs of colors that are opposite each other on the color wheel and therefore are opposite hues.

Composition – The arrangement or placement of visual elements in a photographic image.  There are numerous composition techniques (or rules) said to establish a “pleasing” image such as the rule of thirds.

Compression – The process of reducing the size of a file.  When the camera produces jpeg files it compresses data sacrificing a certain amount of image information in order to get the compressed file size.

Contrast – The difference in color and brightness of a subject that makes it distinguishable from other elements of the image.

Converging Lines – Two or more lines that get closer together as they get further away from you.  Often used as a technique to lead the viewer’s eyes into the photograph.


Depth of Field (DOF) – The distance between the farthest and nearest points which are in focus.  Depth of Field can be either shallow or great and can be manipulated by adjusting several factors such as lens focal length, aperture, and shooting distance.

Diaphragm – An adjustable element of a lens that consists of overlapping metal “leaves” that open and close as the aperture setting is changed.

Diffuser – Any material used in photography to soften the light reaching a subject by scattering it.

DPI – Dots Per Inch. A measurement of the resolution of a digital photo. The higher the number, the greater the resolution.

DSLR – Digital Single Lens Reflex.  The digital version of an SLR camera it uses one lens for taking and viewing the image in conjunction with a mirror (the reflex part).


EXIF Data – Exchangeable Image File: the file format used by most digital cameras.  Usually consists of the JPEG file format along with metadata tags.

Exposure – The quantity and amount of light allowed to reach and react with the film or image sensor.  Exposure is a product of the intensity (controlled by the aperture) and the duration (controlled by the shutter speed) of light hitting the film or sensor.

Exposure Compensation – The practice of allowing more or less light into the camera than the light meter suggests is appropriate.  Strongly back lit scenes or those with light reflecting off of a bright surface may cause the in camera light meter to register the wrong exposure.  Exposure compensation allows for manual adjustment to a more accurate exposure.

Exposure ModeSettings on the camera that determine the aperture and shutter speeds.  Most digital cameras have a range of modes from completely automatic to completely manual.  In between are aperture priority, shutter priority and usually a range or scene modes.



f-number A ratio of the focal length of the lens to the diameter of the aperture.  Each f-number lets in twice as much light as the next higher one, and half as much light as the next lower one.  The f-number affects the depth of field.

f-stopsee f-number

Field of ViewThe diagonal measure of the part of a scene that is visible with a given lens.

Fill FlashA technique that combines flash illumination and ambient light to brighten deep shadow areas.  The aperture and shutter speed are adjusted to correctly expose the background and the flash is fired to lighten the foreground.

Film Speed The sensitivity of the film or sensor to light indicated by ISO number.  The higher the number, the more sensitive or faster (and more grainer/noisey) the film or sensor.

Filter – A device, usually made of glass, that covers the lens to emphasize, change or eliminate the color of the scene being shot by absorbing light.

Fisheye Lens– An extremely wide angle lens that produces an image with a distorted view (usually circular) of the scene by giving a 180 degree angle of view.

Flare Also referred to as lens flare it is when non-image forming light enters the lens and hits the film or image sensor resulting in unwanted (usually) fogging or halos of light in the image.

Flash Meter – An instrument, either built into the camera or separate from it, for measuring the amount of light produced by a flash unit used to determine the appropriate exposure.

Focal Length –  The distance in mm from the optical center of the lens to the focal point on the sensor or film if the subject is in focus.

Focal Plane – The flat plane onto which a lens focuses its image.

Focal Point – The point on the optical axis where light rays form a sharp image of a subject.

Foreground – The area in front of the subject, in between the camera and the subject.

Framing – A way to draw attention to the subject of an image by using other parts of the image as a frame around the focus.


GIF – stands for Graphics Interchange Format and is one of the two most common file formats for graphic images on the World Wide Web.

Grain – The film photography equivalent to noise in digital photography.  Sand like speckles that can appear in a print as the ISO and enlargement of the print get larger.


Histogram – A graph on a digital camera, usually displayed on the LCD screen, used to evaluate the exposure of an image.  The graph shows how the tonal values of the image are distributed with black on the left and white on the right. Underexposed images have the graph bars bunch up towards the left or black end while over exposed images have the bars bunch up on the right or white side.  Perfectly exposed images have an even distribution of bars.

Hot Shoe – An electrical contact point, usually on the top of the camera, used to connect the flash to the camera in order to allow it to communicate with the camera and fire based on the camera flash settings.

Hue – One of the properties of color along with saturation and brightness.  It is the name of the colors on the spectrum, such as red, yellow or blue.  Technically, it is the particular wavelength frequency.


Image Sensor – The device in a digital camera that converts light into an electrical signal which is then converted into digital data to produce the image.

Image Stabilizer – A mechanism in many digital cameras designed to counteract camera shake especially with hand held long shutter speeds.  It can be built into either the camera itself or the lens.

Incidental Meter –  A device used to measure the amount of light falling on a subject for purposes of determining the correct exposure settings.

Infinity – Focusing point at which the lens gives a sharp image of very distant objects, such as the far horizon.

ISO – International Standards Organization.  A common reference for film speed.


JPEG– Stands for Joint Photographic Experts Group and is a method of image file compression.  It typically results in some file data being lost in order to achieve the compression.




Lens – An optical element attached to a camera (either permanently or interchangeable) made of glass or plastic and capable of bending light and focusing it on film or the digital image sensor.

Lens Hood – A collar attached to the front of a lens that keeps unwanted light from striking the lens and causing image flare.   The hood may be attached and often collapsible or detachable, and should be sized to the particular lens to avoid vignetting.

Lens Mount – The point of contact on the front of a SLR or DSLR camera where the lens is attached.

Light Meter– A light sensitive device either built into the camera or a separate piece of equipment used for evaluating the amount of light in a scene to determine the correct exposure setting. There are four types: Incidental meter, reflective meter, flash meter and spot meter.

Light Tent – A tent like structure made of translucent material hung around a frame. The intent is that the fabric diffuses the light coming from outside the tent so that the  subjects placed inside the tent can be photographed without reflections.  Often used for product photography.


Macro Close up photography where the image projected on to the film or digital sensor is about the same size of the actual subject.  Most often seen with subjects such as flowers and insects or other small objects.

Matrix/Multizone MeteringA metering system that relies on more than one area of the subject to get a meter reading resulting in a more accurately exposed image.

Megapixel– The equivalent of 1 million pixels.  Often seen as a measurement on a camera such as 10 mp meaning the camera’s digital sensor can capture 10 million pixels.

Metadata– Data recorded by the camera onto the image file which specifies details about the image such as the type of camera the image was shot with, exposure settings, focal length and the like.

MeterGenerally refers to a device in or attached to the camera that measures light for the purpose of determining the best exposure to capture the image.

MonochromaticIn photography where the overall color scheme of an image is based around varying tones of one color.

MonopodA device with a single leg used to support a camera when hand holding and a tripod are not appropriate.


Neutral Density FilterAlso referred to an ND Filter or a gray filter.  It reduces light of all colors equally in order to allow more flexibility with aperture and shutter speed particularly in extreme conditions.

NoiseThe digital photography equivalent of film grain.  In a digital image noise appears as mis-colored speckles and results from several factors including the ISO setting in the camera, length of the exposure, and temperature.

Normal Focal Length The focal length that generates an image that appears the same as it would to the naked human eye versus wide angle or telephoto.  The normal focal length for any particular lens is equal to the diagonal size of the film or sensor format. For a 35 mm camera the most common normal focal length is 50 mm.  For digital cameras, with the exception of full format, the sensor is usually much smaller than 35 mm film.  Therefore normal is based on the 35 mm equivalent.


Optical AxisAn imaginary line passing horizontally through the center of the lens system.

Over ExposureA condition in which too much light reaches the film or sensor causing the image to appear too light or washed out.



PanningMoving the camera along with a moving object so that the image of the moving object remains in the same relative position in the viewfinder as you take the picture. The effect creates a sharp subject but a blurred background giving a sense of movement in the image.

PanoramaA picture of a continuous view of a landscape, produced either by using a panoramic camera or from a composite of several images.

PerspectiveThe relationship of the size and shape of a three dimensional subject to its two dimensional surroundings.

PixelThe building blocks and smallest piece of information in a digital photo.  The are comprised of squares or dots of color that when combined together make up the image.

PolarizerA colorless gray filter used on a camera lens to reduce or remove reflection from surfaces such as water, glass and other shiny surfaces.

Post ProductionThe step in the photography process that occurs after the shoot.  Usually involving post production software such as PhotoShop.

Prime LensA lens with a single, fixed focal length and no zoom.



RAW – An image format with no in camera processing.  Processing of the file needs to be done in another, off camera, software program.

Reciprocity – In photography reciprocity refers to the relationship between the aperture (f-stop) and shutter speed.  Each f-stop has a corresponding or reciprocal shutter speed that will result in a correctly exposed image.

Reciprocity Failure – The situation when the shutter speed required to get a correct exposure for a give aperture is outside of the normal linear range for the film.  Reciprocity failure is not an issue with digital cameras.

Red Eye – When the pupils of a subject’s eyes appear red in an image.  The cause of red eye can be attributed to low ambient light or a small angle between the lens and the flash causing the light to bounce back from the eye’s retina and make the blood vessels show in the image.  It can be reduced by increasing the ambient light, increasing the lens to flash angle, having the subject look into a bright light or with the red eye reduction feature on the camera.

Reflective MeterA device used to measure the amount of light reflected by a subject about to be photographed for purposes of determining the correct exposure settings.

RGB – Red, Green and Blue.  The three colors visible to digital cameras that when combined at various levels form all the other colors that make up the image.  100% of all three colors yield white and 0% of all three yields black.

Rule of Thirds – A method for composing and cropping an image that divides the pane into three horizontal and three vertical panes.  According to the rule, image composure is best when strong horizontal and vertical lines fall into the top and bottom or left and right thirds rather than the middle. Objects are also best placed at the intersection of the lines.

Rule of Thirds layout


Saturation– The richness of the colors in an image relative to one another.

Scene Modes – Automatic exposure modes found on most digital cameras that set the aperture and shutter speed based on the subject or setting.  Common modes include portrait, sunset, night, action, and macro.

Sensor – The device in the camera that converts the light allowed in by the shutter into an electrical signal.  The electrical signal is converted into an image by the camera’s processor.

Shutter Priority – An exposure mode that allows the camera to set the aperture based on the shutter speed set by the user.

Shutter Release – The button on the camera that activates the opening and closing of the shutter.

Shutter Speed – The amount of time the camera shutter is open determining the exposure of the image.  The faster the shutter speed the shorter the exposure.

SLR – Single Lens Reflex.  A camera that uses a mirror and prism to allow the user to see the subject through its one lens.

Spot Metering – A metering method used to get accurate light readings from just a small part of a subject. It uses a narrow angle of view to measure within the limited areas specified by the camera setting.

Stop Down – Reducing the size of the lens aperture (increasing the f-number) allowing less light to reach the film or sensor and resulting in a greater depth of field.

Stop Motion – Photographing a moving subject with a shutter speed high enough to stop the subject and keep it in focus.



Teleconverter A device made of special glass used to increase the effective focal length of a lens. It is mounted between the camera and the lens and usually comes in three different sizes: 1.4X, 1.7X and 2.0X.

Telephoto Lens – A lens with a long focal length.  Telephoto and zoom lens are often confused but are not one and the same.

TripodA device with three legs used to support a camera when hand holding is not appropriate such as for long exposures.

Tungsten A term used to refer to most light bulbs.  The light from tungsten bulbs makes objects appear a reddish/yellow color.  There are special filters and white balance settings on digital cameras for correcting the color cast from this light.


Under Exposure A condition that results in a dark image when too little light is allowed to reach the film or digital sensor.

UV FilterA device, usually made of glass, that covers the lens to reduce ultraviolet light exposure to the film or digital sensor.  A UV filter is generally not needed for most modern DSLRs and as the sensors are not sensitive to UV light.  This filter is often used however to protect the lens.


ViewfinderThe device (or window) that the photographer looks through to frame the subject.  The viewfinder windows in most DSLR cameras have readings such as exposure settings and focal points.

VignettingThe effect seen in an image resulting from blocking the light at the edge of the image.  It can be caused accidentally by a combination of wide-angle lens and filters or lens hoods, or on purpose as a intentional effect.


White Balance An adjustment that compensates for and corrects the imbalance of color caused by various light sources so that white objects appear white.  For example the yellowish/orange color when photographing under tungsten lamps.

Wide Angel LensA lens that has a focal length and angle of view that is shorter than that of a normal lens.




Zoom Lens A lens which has a adjustable focal length allowing you to change magnification in order to get a closer or farther view of your subject.  Often confused with a telephoto lens.


35 mm Equivalent – The focal length of the lens in the digital camera, as it compares to a 35mm film camera lens.  The 35 mm equivalent focal length of a particular lens-sensor combination in a digital camera is the focal length that one would need for a 35 mm film camera to obtain the same angle of view.