How Does a Light Meter Work?

The art of photography is basically the capture of shadow and light, and these components are what determine the exposure of a photo. In order for photographers to gauge the amount of shadow and light, they use light meters that are either handheld or built into a camera. A light meter tells photographers what aperture settings they should use with a particular shutter speed. This informative guide answers a very common photography query: how does a light meter work?

The working parts

Light meters are composed of a light sensor that is usually made from selenium, silicon or cadmium sulfide. Both cadmium sulfide and silicon require a power source, such as a battery, to work. Selenium does not; it produces enough power on its own to move the needle on the meter. These parts works together to produce two types of light meters: analog and digital.

Analog light meters

Analog meters have dials and a needle with a row of exposure numbers. After the speed is set on a dial, the photocells are exposed to light, causing the needle to adjust. The exposure dial is then set to match the needle's position. This lets the photographer know where to set the aperture opening and shutter speed.

Digital light meters

Digital meters are similar to analog models, except for the digital readouts that give the ideal exposure setting for light conditions. Cameras with built-in meters use reflected light - or light from the entire scene. Handheld digital meters also use this type of light, but these devices are intended to read incidental light by focusing on the subject being photographed.

For novice photographers, learning how a light meter works is simple with this helpful guide. When you use a meter to generate the right combination of shadow and light, it gives your photographs a truly professional appearance.