Panchromatic

Photo material that is sensitive to all colors that the human eye can perceive.

Panning

The act of following a moving subject with the camera while releasing the shutter.

Panoramic

In photography, an image proportionally more rectangular than a 35mm film frame. 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 representation of three-dimensional space in a two dimensional medium. Three dimensions are implied by converging lines and a focal point.

Photoflood

Tungsten light source with a metal reflector. Typically either 5500K or 3200K.

Photography

From the Greek Photos and Graphos, light writing or writing with light. The mix of art, craft and science for the creation of images on a light sensitive surface (such as film or a CCD).

PICT

A Macintosh graphic imaging file format using a pct extension (*.pct). May contain object-oriented and bitmapped graphics.

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.

Pixel

Contraction of Picture and Element. Any of the small discrete elements that together constitute an image (as on a computer or television screen or CRT), or any of the detecting elements of a charge-coupled device used as an optical sensor in a digital camera. Each one has a specific color and is contiguous to the next to form a color image.

Plane

An imaginary line, flat area or field which lies perpendicular to the optical axis.

Polarization

Use of polarizing filters to control the direction light travels. The effects are minimizing glare and reflections and saturation of colors, 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.

Portrait Lens

Usually a lens with a moderately long focal length (80 to 135mm in 35mm cameras). Sometimes they have slight diffusing glass.

Positive

A photo 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, transparency or color reversal.

Posterization

Banding or lack of continuous tones in an image. Can be a deliberate effect or, more commonly, a result of over-manipulation or compression in a digital image.

PPI

Pixels per square inch. The greater the number, the better the image quality.

Preset Focus

The act of focusing at a predetermined distance to shoot a moving subject as it goes by the focus point. A technique employed with both manual lenses and when locking focus with auto lenses in anticipation of fast moving subjects. Freeze Focus is a feature by which the shutter is automatically actuated when the subject reaches the preset focus point.

Primary Colors

Red, yellow and blue, the three colors which combined make white light.

Prime Lens

A lens with a single, fixed focal length; not a zoom lens.

Principal Point

A point from where the focal length of the lens is measured. Normally located at the center of the lens. However, compound lenses have two principal points, and the location of these principal points cannot be determined by appearance.

Prism

A piece of transparent material (i.e., glass or plastic) that is capable of bending light.

Processing

In photography, chemical process where a latent photographic image is converted to a stable visible image.

Projector

A device used to enlarge images by focusing light through them onto a flat surface.

Pulling

To overexpose and underdevelop film to effectively reduce its speed.

Pushing

To underexpose and overdevelop film it to effectively increase its speed.