What is a light meter and when would you use it?

• A. Measures light to determine correct exposure; use incident or reflected readings to achieve consistent exposure across scenes and gear.
• B. Measures color temperature only.
• C. Used to autofocus lens.
• D. Measures flash recycle time.

Answer: (A)

A light meter measures the amount of light in a scene to determine the correct exposure, helping you set the camera's aperture, shutter speed, and ISO so your images stay properly bright or properly dark across different scenes and gear. You can take an incident reading, which gauges the light falling on the subject with the meter’s dome, giving you exposure that’s independent of the subject’s color or reflectivity. Or you can take a reflected reading, which measures the light bouncing off the subject, useful when you can’t place the meter in the lighting path but requires you to account for subject tone and texture. A light meter isn’t for focusing a lens, nor is it limited to color temperature, and it isn’t about flash recycle time. In practice, using a light meter lets you create consistent exposures from scene to scene and across different lighting setups and equipment.