January 6, 2018

A Cinematographer's Best Friend: How to Use a Light Meter

Light meters are one of the most helpful and powerful tools that DPs have at their disposal, but how exactly do you use them?

As a cinematographer, light is your most important material for crafting your scenes, but it can be a very tricky thing to have control over. This is why it's so important to understand how to use a light meter, a device that helps you determine proper exposure and the best light level for a particular scene. In this video from Aputure, DP Julia Swain not only explains how light meters work but also shows you how to use them when you're trying to come up with the optimum lighting setup for a shot. Check it out below:

There are a number of different ways to measure light, including using monitors with a variety of scopes (waveform, histogram, zebra), but using light meters is a relatively quick and easy way to determine exposure to get the lighting setup your scene needs.

While setting the parameters (ISO, frame rate, etc.) on a light meter is pretty straightforward, it might take a little practice to actually decide what to do with the readings it gives you. As Swain says in the video, getting a certain reading doesn't automatically mean you have to set your aperture to that f-stop. It's up to you to decide whether you want to over or underexpose your image, add more light to achieve a specific light ratio, or change your lighting setup altogether.       

Your Comment


This video is not covering this topic in a very informative way.
1 - NEVER stand on the side of the source of light to measure exposure on the subject (as it is shown in the "Onset example"), especially wearing a black tee-shirt (white would even worst), as the source of light is a mixture of the light itself and its potential reflection (or absorption) by the environment. By standing on the source of light side, you just modify the "lighting" environment (and therefore the exposure) as you are not going to be there while shooting. Best is to stand on the opposite side of the source of light while measuring it on your subject.
2 - The spot metering (reflective value) has to fall on something calibrated such as a grey card or (by default) an average skin to deliver a useful value. Spot metering is very important, for example, to be sure that the enlightenment of the whole surface of a green screen is even or to calculate the contrast ratio of a complete scene by comparing the brightest/darkest part values to check if it falls in your camera dynamic range.

January 7, 2018 at 4:39AM, Edited January 7, 4:41AM

Franc Sanka
Director of Photography / Film and Photography Teacher

Great addition!

January 7, 2018 at 7:36AM

Director, DOP, Writer, Editor, Producer

What is her name?. She talks fast and slurs words. Tried to Google her but got nowhere.

January 12, 2018 at 2:45PM, Edited January 12, 2:46PM

Mark Pope