Words To Know And Understand As You Explore Photography
Aberration: A lens defect, resulting in image distortion.

AE: Automatic Exposure, Autoexposure. Mode in which the camera adjusts shutter speed and aperture to achieve correct exposure.

AF: Automatic Focus, Autofocus. System by which the camera and lens adjust to focus on a specific part of the image.

Ambient Light: Light that already exists in a scene, either natural (sunlight) or manmade (artificial).

Angle of View: Measures the area a lens can cover (e.g., wider coverage = larger angle).

Aperture: The size of the lens opening through which light passes, expressed in f/stops (focal length divided by diameter of aperture).

Aperture Priority: Mode of automatic exposure in which the camera adjusts shutter speed according to a manually selected aperture.

Archival: Method of processing designed to protect photographic materials from long-term deterioration. If processed correctly, silver-based materials are, by nature, archival. Color materials, due to deterioration of their organic dyes, are not archival. Also refers to any method of storage, analog as well as digital, that will not deteriorate over time.

ASA: An old film sensitivity rating, replaced by ISO.

Aspherical Lens: Type of lens that is ground a particular way to better correct for spherical aberration. Results in better, more compact lenses.

Astigmatism: Aberration that causes an image to not focus uniformly.

Back Lighting: Light from behind the subject, heading toward the camera

Barrel Distortion: Lens aberration that causes straight lines to bow out, away from the center.

Bellows: An expandable, flexible, light-tight, accordion-folded instrument used in view cameras to connect the lens to the film plane, as well as in other formats for close-up photography.

Bracket: To make multiple exposures, some overexposed and some underexposed according to the indicated meter reading, used to control brightness, contrast, color and to ensure accurate exposure.

Brightness: A subjective impression of the lightness of an object.

Bulb: Shutter speed setting, marked B, that holds open the shutter as long as the release button is held down.

Burn: To darken a specific image area during printing by giving it additional exposure.

C-41: Standard process for developing color negatives.

Camera: A picture-taking device, usually consisting of a light-tight box with a film, shutter and lens.

Chromatic Aberration: Lens aberration that focuses different colors of light at different angles.

Chrome: Slang term for slides or transparencies.

CMYK: Acronym for Cyan, Magenta, Yellow, Black, the primary subtractive colors and black. CMYK commonly refers to a type of the ink colors used in color offset printing.

Color Balance: A film's or paper's response to specific colors of light. Films are adjusted for optimum color reproduction in specific color temperatures of light (i.e., tungsten or daylight-balanced)

Color Temperature: Numerical measurement of the color of light, measured in degrees Kelvin. Warm is low, cool is high. Normal daylight is approximately 5500 degrees Kelvin.

Continuous Tone: An image possessing a smooth gradation of tones through the gray scale, from pure black to pure white.

Contrast: The difference in brightness between different light and dark tones within a scene.

Convergence: Lines that are parallel in reality appear non-parallel in an image because of the picture-taking perspective.

Cool: Description of bluish colors, or light, or color balance, that is associated with cold temperatures.

Crop: Adjusting the edges of an image, typically to improve composition.

Daylight Film: Color film balanced to produce accurate colors when exposed in normal sunlight, or with electronic flash, or any other light source with a color temperature of approximately 5500K.

Dedicated Flash: Electronic flash that must be used with specific cameras to automatically adjust the camera's exposure controls to produce the correct exposure.

Density: Indirectly refers to the amount of exposure in a transparency or negative. In negatives, overexposure results in increased density, underexposure causes less density. In transparencies, the opposite is true.

Depth of Field: The area in a scene that is in acceptable focus. As aperture size or focal length increases, depth of field decreases.

Develop: Chemical process used to convert a film or paper's latent image into visible tones. Also used to describe the entire process of development and fixing of an image in an emulsion.

Diffuse: Light that is scattered, spread out and not coming from a single point. For example, light on a cloudy day is diffuse.

Diopter: Optical term for the power of a lens. Photographically, it is typically used to indicate the magnification and focal length of close-up lenses.

Distortion: Changes in perspective or aberrations that cause straight lines to appear curved.

Dodge: To lighten specific areas of a print by decreasing their exposure to light.

DPI: Dots Per Inch. Used in digital imaging to indicate an aspect of an image's measurable resolution.

DX Coding: A code on most modern film cassettes used by the camera to automatically adjust ISO setting.

E-6 : A process used to develop certain types of color transparency film.

EI : Exposure Index. A non-standard film-speed rating, used to indicate a photographer's "working" film speed when it differs from the manufacturer's rated ISO.

Emulsion: A light-sensitive coating applied to film or paper. Latent images form in the emulsion, and are made visible and permanent during development.

Enlargement: A print from film made by projecting the image onto sensitized paper.

EV: Exposure Value. Developed in order to simplify numbers used in exposure calculations. Currently used to describe the range of exposure in which equipment can successfully operate.

Exposure: The amount of light falling on a sensitive material. Controlled with aperture and shutter speed settings.

Exposure Meter : Light Meter. Device used to measure the amount of light falling on, or reflected from, an object.

Extension Tube: Metal ring attached to a lens that extends the distance from film to lens so that it may focus at closer than normal distances.

Factor: Frequently called Filter Factor. A numerical rating indicating how many times exposure must be increased to compensate for loss of light caused by the density of the filter.

Fast: 1. Term used to describe a film or paper that is very light-sensitive. 2. Indicates the speed of a lens, based on the maximum aperture (very wide opening). 3. A very short shutter opening duration.

Film: Translucent material coated with an emulsion and placed in a camera to record images. Typically acetate- or plastic-based.

Film Holder: Light-tight container used to hold film for exposure in a view camera.

Film Plane: Also called focal plane. The plane on which a lens focuses a sharp image.

Film Speed: Measured with ISO rating, it is a film's sensitivity to light. Speed increases as sensitivity increases.

Filter: A piece of optical plastic or glass used on a lens to modify light in a variety of ways before it reaches the film or paper.

Fisheye Lens: An extreme-wide-angle lens in which all lines appear to curve around the center.

Flare: Extraneous light entering a lens, scattering and producing a loss of image contrast and/or odd light patterns.

Flat: A scene that is low in contrast.

Focal Length: A measurement of the size of a lens, usually in millimeters. Larger lenses produce increased image magnification.

Focal Plane Shutter: A camera mechanism that allows light to expose film by moving curtains in front of the film plane.

Focal Point: The point at which an image is sharp.

Focus: The point where light converges to form a clear, sharp image.

Fog: General density in an image caused by unwanted exposure or chemical activity.

Frame: 1. The area of an image. 2. A single image in a roll of film.

F-stop: Common term used to define lens aperture setting (the ratio of focal length divided by diameter of aperture)

Grain: The silver halide crystals that compose a photographic emulsion.

Graininess: A subjective measure of the visible clumping of grains in an emulsion. Different from Granularity.

Granularity: An objective measure of the size differences of grains; granularity effects visible graininess.

Gray Scale: A scale of tonal values reproducible in black and white printing.

Ground Glass: A flat piece of glass that is roughened on one side so that an image focused on it can be seen. Used as the viewing screen in view cameras.

Guide Number: A numerical valuation for the power of a flash. Used to determine the aperture that will produce correct flash exposure with a given ISO and distance from flash to subject. Guide Number = f/stop x Distance.

Halftone: Image reproduced with black dots (spaced close together for dark areas and far apart for light areas) that gives the illusion of a continuous tone print.

Handheld: The act of making an exposure with the camera held by hand, rather than mounted on a tripod.

Head (Tripod Head): The usually removable top of a tripod that allows various movements and adjustments of the mounted camera. Two main kinds: ball head (a ball and socket type of joint is used to adjust camera position) and pan head (various adjustments can be made to move the camera in a specific plane).

High Key: Describes the overall brightness of a scene that is very light and bright.

Hot Shoe: A mounting bracket on top of a camera that is used to attach and establish electrical connection with a flash.

IF: Internal Focus. A type of focusing where the lens elements move within the lens barrel, without changing the external movement or length of the lens.

IS: Image Stabilization. Mechanism within a lens that helps reduce blurring due to minor camera motion.

Ilfochrome: Formerly Cibachrome. A type of color printing that produces positive prints directly from transparencies.

Incident Light Meter: A meter that measures the amount of light falling on a subject.

Infinity: The farthest position on the distance scale of a lens.

Infrared: Light beyond red on the color spectrum, and therefore invisible to the human eye. Some photographic materials are sensitized to record infrared light.

Instant Film: A film that contains the necessary chemicals for development, so it can be processed right after exposure.

Interchangeable Lens: A lens that can be removed from a camera and replaced with a different lens.

Inter-Neg: A negative that is made from a transparency image in order to produce standard type-C color prints.

ISO: Numerical rating describing a film's sensitivity to light (replacing ASA and DIN). ISO number doubles as a film's sensitivity doubles.

K-14: The chemistry used to process Kodachrome film.

Kelvin Scale: Used to measure and define the color temperature of different light sources.

Latent Image: Image formed by the changes to silver halide grains in photographic emulsion upon exposure to light, which is not visible until chemical development occurs.

Latitude: The range of exposure (+/-) in which a photographic emulsion will produce a usable image.

Leaf Shutter: Type of shutter mechanism that opens and closes a circle of overlapping leaves to allow light to expose film; usually a part of the lens.

Lens: A piece (or multiple pieces) of optical glass that is shaped to focus an image.

Lens Shade (Lens Hood): An attachment to the front of a lens that prevents extraneous light from shining directly onto the lens and producing flare.

Light Meter (Exposure Meter): A device that measures illuminance and luminance, allowing the photographer to determine the correct exposure.

Light-Tight: Refers to any container that is absolutely dark inside, allowing no unwanted light to penetrate.

Long Lens: Slang for a telephoto lens (a lens whose focal length is longer than the diagonal measurement of the film used).

Luminance: The light reflected by, or emanating from, a surface.

Macro Lens: A lens designed to produce very high sharpness when focused up-close; a lens that produces a ratio of 1:1 when used up close.

Manual Exposure: A mode of camera operation in which all exposure settings are determined and set by the photographer.

Matrix Metering: (Also called Evaluative Metering and Honeycomb Metering.) Advanced TTL metering system that uses simultaneous readings from multiple image areas to determine the correct exposure.

Middle Gray: A standard gray tone that reflects 18 percent of light falling on it. When a meter determines exposure, it assumes the subject it sees is middle gray.

Midtone: The subjective impression of an area of medium brightness, similar to middle gray.

Monopod: A single leg (as in a tripod leg) with a mounting bracket used to steady cameras. Typically used when a tripod is impractical.

Movements: The adjustments a view camera can make: tilt, shift, swing, rise and fall. Typically used to adjust plane of focus, distortion and perspective.

Negative: Film that produces an image with brightness levels opposite of the actual scene (black is white, etc.) and must be printed to produce a positive image.

Neutral Density: A type of filter used to decrease the amount of light entering a lens. Also called ND Filter.

Normal Lens: A lens with a focal length approximately the same as the diagonal measurement of the film being used. This produces an image that approximates the same angle of view and perspective of the human eye.

Open Up: To increase the size of the aperture by adjusting the f/stop to a smaller number.

Overexpose: To give more than the normal exposure to film or paper.

Pan: To follow the horizontal movement of an object.

Parallax: The difference in point of view that occurs when the taking lens is separate from the viewing lens.

PC Connector: Synch Cord. The electrical cord that connects an off-camera flash with the camera so that they may synchronize.

Perspective: The apparent size and depth of objects in a scene, related to point of view.

Plane of Focus: The plane in which objects in a scene are critically sharp.

Point and Shoot: (Subjective term.) Typically automatic or with minimal adjustable controls, these cameras are used for easy photography. The name comes from the idea that the cameras are so simple the photographer need only point and shoot.

Polarizing Filter: A filter that affects light in 4 ways: darkens the sky at 90 degrees from the sun; eliminates reflections; saturates color; reduces haze.

Positive: Any photographic image with tones corresponding to the subject. The opposite of a negative.

Primary Colors: Red, Green, Blue (RGB). The basic colors of light from which all other colors can be mixed. Also called Additive Primary Colors.

Print: A photographic image, usually a positive, on paper.

Processing: The act of chemically developing and fixing an image on film or paper.

Program Mode: An automatic exposure mode in which the camera adjusts all aspects of exposure.

Proof: A test print made for evaluation purposes, whether for content or technical quality.

Push: To expose film at a faster speed rating (EI) than that specified by the manufacturer (ISO), then compensated for the underexposure by overdeveloping.

Rangefinder: A camera equipped with a device that measures the distance from camera to subject for focusing.

Reciprocity Failure: Loss of predictable sensitivity in a photographic emulsion due to very long (more than one second) and very short (faster than 1/10,000th) exposures.

Reflected-Light Meter: A light meter that measures luminance, the light reflected off an object.

Reflex Camera: A camera with a built-in mirror that reflects the scene being focused by the lens onto a ground-glass viewing screen. Available with one lens that acts as both viewing and taking lens (Single-Lens Reflex, SLR) or with separate lenses for viewing and taking (Twin-Lens Reflex, TLR).

Resolution: A subjective valuation of the detail-recording ability of photographic materials.

Resolving Power: A measurement of the detail-recording ability of photographic materials.

Reversal Film: Transparency/Chrome. Film that produces a positive image upon exposure and development.

Roll Film: Any film that is packaged in rolls (typically for multiple exposures) rather than single-exposure sheets. Usually refers to medium formats, not 35mm.

Sharpness: Subjective description of an image's focus and resolution.

Sheet Film: Film that is used as individual, single-exposure flat pieces.

Short Lens: Term describing a wide-angle lens (a lens whose focal length is shorter than the diagonal measurement of the film used).

Shutter: A camera mechanism that opens and closes to allow light to enter the camera for a specific amount of time in order to expose the film.

Shutter Priority: A mode of automatic exposure by which the photographer manually adjusts the shutter speed, and the camera adjusts the aperture accordingly to produce a normal exposure.

Silhouette: A scene in which the background is brighter than the subject, producing a detail-less, shadowed subject.

Silver Halide: The light-sensitive parts of a photographic emulsion; compounds of silver chloride, silver bromide and silver iodide.

Slave: An electronic unit that is triggered when it detects a burst of light or other type of signal (radio, digital, etc.). Used to control various photographic devices, including shutter releases, flashes, motion sensors, etc.

Slide: A transparency that is mounted for insertion into a projector.

Slow: Term referring to: 1. photographic emulsions that are not very light-sensitive, 2. lenses whose maximum aperture is not very large, 3. long shutter speeds.

SLR: Single Lens Reflex camera. One lens acts as both viewing and taking lens.

Soft: Term describing any part of an image that is not in focus.

Speed: Refers to the sensitivity of a photographic emulsion, or the ability for a lens to accommodate light.

Spherical Aberration: A lens defect that causes lines at the edges of a lens to be bent more than lines toward the center.

Spot Meter: A reflected-light meter with a very small angle of view, used to measure brightness of a small portion of a scene.

Stop: An aperture setting, or shutter speed setting, on a lens or camera. Also, a change in exposure by a factor of two.

Stop Down: To decrease the size of an aperture. The opposite of opening up.

Strobe: Loosely refers to an electronic flash, or any light source that emits light in very short bursts.

Synch Cord: PC Connector. The electrical cord that connects an off-camera flash with the camera so that they may synchronize.

Synchronize: To cause two events to occur simultaneously (as in a shutter opening and a flash firing).

Telephoto Lens: A lens that magnifies an image and produces a narrowed angle of view. As the focal length increases, the magnification increases and the angle of view decreases.

Tone: The lightness or darkness of a particular area. Also, to color a print by immersion in a chemical solution.

Transparency: Film in which the final image is positive. Often used interchangeably with chrome, positive and slide.

Tripod: A three-legged stand used to hold a camera steady during exposure.

TTL: Through The Lens. A type of scene metering in which the camera accepts information directly through the lens. (For example, a TTL light meter or TTL flash meter.)

Tungsten Film: Often called Type B. Film that is balanced to record color correctly under tungsten lighting.

Tungsten Light: Light that is roughly 3200 degrees Kelvin in color temperature.

Type C Print: The standard form of printing color negatives into positive prints. Commonly called a "C-Print."

Type R Print: A method for printing transparencies into positive prints, without making an inter-neg.

Ultraviolet Light: Light that is just beyond violet on the visible spectrum.

Underexpose: To give less exposure than normal. Produces less density in negatives, more density in transparencies.

Value: The relative lightness of an area. Low values are dark, high values are light.

View Camera: A camera with movements in which the taking lens forms an image directly on a ground-glass viewing screen. A film holder is inserted in front of the ground glass for exposure. Also called large-format camera (typically producing images 4x5 inches or greater).

Viewfinder: A small window on a camera through which the scene is viewed.

Viewing Lens: The lens on a camera through which the photographer's eye sees the subject.

Viewing Screen: The ground-glass element in a camera on which the subject is viewed.

Vignette: An image with underexposed or overexposed (lighter or darker) edges.

Visible Spectrum: The electomagnetic spectrum of visible light; red, orange, yellow, green, blue, indigo, violet.

Warm: Reddish colors that are commonly associated with objects that are warm.

White Light: Light containing equal amounts of the primary additive colors of light. The human eye sees this light as colorless.

Wide-Angle Lens: A lens whose focal length is shorter than the diagonal measurement of the film used.

Zone System: A method of planning film exposure and development to achieve precise control of tones in a print. Pioneered by photographers such as Ansel Adams and Minor White.

Zoom Lens: A lens with an adjustable range of focal lengths.