What Is a Light Meter?

A light meter is an instrument used to measure the intensity of light. In photography, a light meter is used to determine the appropriate exposure time. With the film sensitivity and shutter speed known, the light meter gives the aperture value for the best exposure. Light meters are also used to control the brightness of the light, or used as a handheld instrument to ensure that the light intensity meets the requirements of the shooting.

A light meter is used to measure

In photography, there are many different types of light meters used. According to the differences in functions and uses, they are mainly divided into light meters and color temperature meters. The light meter for measuring the exposure value is further divided into an incident light meter, a reflection light meter and a hybrid light meter according to different measurement methods. Differentiated by photometric elements, the most common are

Light meters are also used in lighting. Its role is to measure the brightness of the room and reduce or turn off the output of the lamp. They can greatly reduce the energy requirements of a building and greatly increase the efficiency of the lighting system. 20% to 60% of the electricity of a building is used for lighting. Especially in the room where the user does not artificially care about the switch of the light, the light meter is suitable. These houses are: corridors, stairs, halls, etc.

However, it is difficult to successfully use a light meter to control the lighting system. The user must be as satisfied as possible with the work of the lighting system. Too bright, too dark, too sudden, and too often switching can be very annoying and bother indoor users. Therefore, manufacturers use different circuits to achieve undisturbed users:

• Use different circuits to first reduce the brightness of the light before turning it off, so as to prevent the brightness from changing too much when the light is turned on and off

• Delay circuit:

• You must wait for a certain time after switching on and off again

• A certain light intensity should be maintained for a certain time ^[1]