A glossary of terms covering lighting, audio, vision and staging in the event and theatrical industry.
There can be a number of meanings for some terms which can vary from country to country and manufacturer to manufacturer. Information within this guide is indicative and every situation can require a different approach and solution. All care has been taken, however, Image Group NZ accepts no responsibility for inaccuracies. If you have any suggestions, comments or queries regarding this list please contact us.
A lens with a variable focal length. You can adjust the size of the image on a screen by adjusting the zoom lens, rather than making the projector closer to or further from the screen.
ZOOM LENS RATIO
The ratio between the smallest and largest image that a lens can project from a fixed distance. For example, a 1.4:1 zoom lens ratio means that a 10 foot image without zoom would become a 14 foot image with full zoom. Conversely, a 10 foot diagonal image at 15 feet with no zoom would still be a 10 foot image at 21 feet at maximum zoom (15 x 1.4 = 21 feet). A zoom lens is "not as bright" as a fixed lens, and the higher the ratio, the less light output.
A type of profile lantern with two lenses enabling the adjustment of both size of the beam and whether it's hard or soft focus. Essential when working with gobos.
See Zoom Profile