Photographic Glossary (I to P)
The meaning of the more common terms and phrases used in photography…
Image Editor
Computer software used for editing, resizing and manipulation of photographs.
Image Plane
The area at which a lens forms a sharp image, i.e., the film plane if, and when focused correctly.
Incidental Light
Light measured as it falls on a surface, rather than light reflected from a surface. Measured from the subject, not the camera.
Infinity
In relation to camera focus: the horizon.
Infrared
Light not visible with the human eye. Measured at the red end of the spectrum, it can be photographed with special film.
Infrared Compensation Index (IR Setting)
An index mark on a camera lens used to correctly focus infrared film. With most lenses, the focal plane for infrared film is slightly removed from that of visible-light photography.
Internal Focusing System
A system used where the internal elements in the lens are the only parts that move during focusing. This prevents the physical length of the lens from changing, allows for faster focus, reduces aberrations, and allows for ease of use for filters that require specific alignment such as polarizers, graduated, etc.
IS
Stands for "Image Stabilizer". This is available in some Canon EF lenses and compensates for camera shake allowing slower shutter speeds.
ISO
The International Organization for Standardization (ISO) is a worldwide federation of national Standards bodies from some 130 countries. Commonly used to rate film speed (or sensitivity to light) in photography.
Key Light
When lighting a photographic subject, the main light source.
Latent Image
The exposed but undeveloped image on a photosensitive surface.
Latitude
How much variation an emulsion allows while still delivering acceptable exposures, i.e., how "forgiving" a film is.
LCD
Liquid Crystal Display. An information display method. Usually used for external displays on cameras or other electronic devices.
Leaf Shutter
Camera shutter located in the lens. Utilizes a spring with the aperture control device to control the exposure time. Useful because it can be synched with a flash at any speed.
LED
Light Emitting Diode. An information display method. Usually used for viewfinder displays since it can be seen in the dark.
Lens
An optical device used to control and focus light.
Lens Coatings
Thin anti-reflective materials applied to the surface of a lens in single or multiple layers to help reduce light reflection and increase amount of transmitted light.
Lens Hood/Shade
A lens addition used to minimize lens "flare" or unwanted light from reaching the lens.
Light
Radiated energy which forms that portion of the spectrum visible to the human eye.
Light Box
A device for viewing film or slides (Transparancies). Constructed of a light source (usually sunlight balanced fluorescent) behind a glass or plastic surface on which the film is placed for viewing.
Light Meter
A light sensitive device used for evaluating the amount of light in a scene for exposure. There are four types: Incidental meter, reflective meter, flash meter and spot meter
Macro photography
Another name for close up photography. Specifically, any photography where the level of magnification is 1:1 or larger.
Magnification
The size of an image relative to the subject as expressed in a ratio.
Matte Field
A textured surface that disperses light to form a clear image, and is used in viewfinder optical systems.
Meter
Any measuring device. In photography it usually refers to a light meter, although it could refer to a colour meter.
Micro prism
A small number of prisms located on a focusing screen. The micro prisms break up out-of-focus images into small segments that appear fuzzy, allowing focusing on subjects without distinct lines.
Mirror Lens
A lens, which uses mirrors as well as glass elements to control and focus an image. Usually a telephoto lens.
Mode
Mode setting on a camera. Usually the type of exposure method used by a camera, e.g., manual mode, aperture priority mode, picture mode, flash mode, etc.
Monochromatic
An image that contains or appears to contain only one colour.
Motor Drive
A device for automatically winding the film in a camera. Most contemporary cameras have them built-in.
Natural Light
Non-artificial light - usually daylight from the sun.
Negative
A processed piece of film where the image is reversed so that the shadows are light and the highlights are dark.
Neutral Density Filter
A dark, colour-neutral filter used to control the amount of light reaching the film or image sensor.
Newton Rings
Coloured, ring-shaped patterns that appear between two transparent tightly pressed surfaces like glass or film caused by moisture between the surfaces refracting the light.
Normal Lens
A lens where the focal length is approximately equal to the diagonal of the film or image sensor size it's being used for. This is also representative of the field of view of human sight. In APS, approximately 28mm, in 35mm approximately 50mm, in medium format approximately 90mm, and in amateur and semi-professional digital SLR cameras it is 18mm. This can also be called a prime lens.
Over Exposure
When light sensitive material is exposed to too much light resulting in film that is too dense to print or view well. In digital photography it is an image that has been “bleached” out with lots of the image turning to pure white.
Panchromatic
Photo material that is sensitive to all colours that the human eye can perceive.
Panning
The act of following a moving subject with the camera while releasing the shutter resulting in a sharp subject with a blurred background.
Panoramic
An image that views more width than height than a traditional photograph. Also, a type of camera for exposing film in a panoramic format.
Parallax
In rangefinder cameras, the difference between the image seen by the lens and the viewfinder. The discrepancy increases as the subject moves closer to the camera. This does not occur in SLR cameras
Pentaprism
A prism in an SLR camera that allows the photographer to view the image while it is being focused.
Perspective
The visual perception of distance in a photograph between objects.
Photoflood
A tungsten light source with a metal reflector.
Pinhole Camera
A camera with a fixed aperture made by poking a hole in a piece of metal. Usually made from a small enclosed container such as an oatmeal box or small tin.
Plane
An imaginary line which is perpendicular to the optical axis (lens). This usually refers to the film or image sensor.
Point and Shoot Camera
Refers to a compact, usually fully automatic camera which is practical due to it’s size.
Polarization
Use of polarizing filters to control the direction light travels. The effects are minimizing glare and reflections, and saturation of colours, especially in landscapes.
Polarizing Filter
Two pieces of polarizing material which rotate on an axis so that the polarizing effect can be increased or decreased. These are used to decrease reflections and glare and to increase colour saturation.
Portrait Lens
Usually a lens with a moderately long focal length (80-100mm in 35mm cameras). Some portrait lenses use glass with a subtle diffusing or "soft focus" effect.
Positive
A photographic image in which the light areas correspond to light areas in the subject, and the dark areas correspond to the shadow areas in the subject. Also called a slide or transparency.
Posterization
Posterization occurs when a digital image's bit depth (see bit depth) has been decreased so much that it has a visual impact. This usually occurs as a result of over-manipulation or compression of a digital image.
Primary Colours
Red, yellow, and blue, the three colours which combined make white light.
Prime Lens
A lens where the focal length is approximately equal to the diagonal of the film or image sensor size it's being used for. This is also representative of the field of view of human sight. In APS, approximately 28mm, in 35mm approximately 50mm, in medium format approximately 90mm, and in amateur and semi-professional digital SLR cameras it is 18mm. This can also be called a normal lens.
Prism
A piece of transparent material (i.e., glass or plastic) that is capable of bending light.
Processing
In photography, the chemical process by which a latent photographic image is converted to a stable, visible image.
Projector
A device used to enlarge film images by focusing light through an attached lens onto a flat surface.
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