Glossary

A meter reading found in some cameras that takes a measurement from around 10% of the central image area.

An automatic exposure mode which chooses a high ISO sensitivity to help balance dark backgrounds with your subject in flash pictures.

One of two popular methods of camera focusing systems, the other is active. Passive has the advantage over active because it isnt fooled by glass in between the camera and the subject. Its also not dependent on subject distance. It works by measuring the subjects contrast and as such its main downfall is when the subject has no contrast. In such situations, such as snow scene or low light, the lens will focus in and out and may never reach sharp focus. Fortunately many cameras with this system have manual override.

A method of drawing around a subject using a Pen tool to create an editable path. This can be turned into a selection so the subject can be copied or edited.

Another name for a shift lens that has a sliding front panel so the lens can be raised or lowered from its normal position to correct for verticals when shooting from high or low angles. Some also have a swing facility to control depth of field using the Scheimpflug rule.

Stands for Personal Computer Memory Card International Association - a group of 25 companies in 1989 who set worldwide standards for compact removable memory cards. These included Type I, II and III cards and were used to store images in a professionally specified camera or add extra functions to a computer. They have largely been superceded by the much smaller CompactFlash and an adaptor is available for older cameras to take the newer cards.

A multi sided glass prism housed in the roof of an single-lens reflex camera so that the image that's seen be the lens can be viewed through an optical viewfinder above the lens. The light enters through the lens is reflected up by a reflex mirror to the prism and across to the eye.

The name used to describe any accessories that connect to a computer such as card reader, printer or scanner.

The rating of the acid or alkalinity of a solution in a scale from 0 to 14. It's based on the hydrogen ion concentration in a solution. Chemical solutions with higher PH ratings are increasingly alkaline, while lower ones acid. Distilled water is neutral with a PH rating of 7.

Taking photos that tell a news story. Photo journalism is closely related to documentary photography and street photography, but distinguishes itself from those types of photography by being dependent on timeliness (the shots a photo journalists takes are to illustrate news stories and therefore they have to be available for publication quickly) and objectivity (the scenes depicted in the images should be a correct representation of the news events they illustrate). A photo journalist is a photographer who often has to take instant decisions, who always carries photographic equipment, and who regularly has to endure discomforts and sometimes even dangers.

A metering cell that converts light into a small charge that was used in older, non-battery meters or cameras to measure exposure.

A format for storing digital photographs at different resolution settings developed by Kodak. PhotoCD can be order when you have a film processed and the lab will scan in the negatives and add them to a CD. One CD can hold up to 100 images, each stored in five resolution levels. You're asked, when opening a picture, what resolution version is required.

A bright tungsten bulb with a colour temperature of around 3400K that is sometimes used in portrait studios. Most studio photographers prefer the convenience of electronic flash.

Where an image is formed by placing an object directly onto printing paper and exposing it to a light source. Many photographers and artists have tried this technique including pioneers Thomas Wedgwood and Fox Talbot along with the Surrealist, Man Ray, who renamed them Rayograms.

Extremely close up photography using bellows or extension tubes to obtain a magnification larger than lifesize.

Photographs taken using the camera attached to a microscope.

A light sensing device use in drum scanners that's capable of measure extremely low levels of light.

The leading image manipulation software for professional and advanced digital image makers. Now in version CS5.

Another name given to the single, light-sensitive area on a CCD that records unique image detail.

A bitmap image format used by Mac computers.

Lens aberrations that make the borders of an image bow slightly inwards to the centre forming a shape like pincushion.

Short for picture element. A tiny coloured square that forms part of an image. Digital images are made up of thousands or millions of different coloured pixels that appear as continuous tones when viewed by the naked eye.

Occurs when pixels are large enough to be seen individually.

Name given to the type of computer system such as Apple (Mac) and Windows (PC). Many peripherals such as cameras, scanners and printers come with a dual CD that allows downloading, scanning and printing software and drivers to be installed on MAC or PC computers. USB products are often compatible with both types of computer platform.

Term used to describe the latest USB peripherals that can be connected and set up while the computer is left switched on. The manufacturer’s dream of easy connectivity hasn’t fully been realised and the term is often abused as plug & pray!