What device is used to measure the amount of light to determine proper exposure?

• A. Light Meter
• B. Photometer
• C. Light Sensor
• D. Lux Meter

Answer: (A)

Measuring how bright a scene is to set the right exposure is the main idea here. A light meter is the instrument used to quantify scene brightness and translate that into camera settings like aperture and shutter speed (given ISO). Using a handheld light meter, you can measure incident light falling on the subject or, with the right mode, detect reflected light from the scene to guide exposure decisions. This helps ensure the image isn’t under- or overexposed. A lux meter focuses on illuminance in a space and isn’t typically used to dial in camera exposure. A photometer is an older term that can overlap with light meters, but in practice the device used to determine exposure is the light meter. The camera’s built-in light sensor performs metering, but a dedicated handheld light meter gives more precise control in many cinematography and photography situations.