How to Use a Light Meter for Film Photography (Handheld & Built-In)

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Get perfect exposure and an evenly lit subject in every picture

Co-authored by Crystal Bear and Dan Hickey

Last Updated: December 8, 2024 Fact Checked

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Adjusting Your Settings

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Using a Handheld Meter

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Using a Built-In Meter

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How does a light meter work?

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Video

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Expert Q&A

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Tips

Digital cameras have in-camera light meters, but they can meter the wrong area in the image or read the light reflecting off certain colors incorrectly, resulting in a poorly exposed picture. A handheld light meter reads the light at the point of intended exposure with much greater accuracy and can be used with a digital or non-digital camera. In this article, we’ll show you how to adjust your camera settings and use both a handheld and built-in light meter for the perfectly lit photograph (with expert tips from professional photographer Crystal Bear).

How to Work a Light Meter for Perfect Exposure

Adjust your film camera and light meter to the same ISO and aperture settings. Hold the meter close to the subject’s face with the lumisphere (white dome) facing the light source (if the meter is incidental) or the camera (if it’s reflective). Press the measuring button to get the ideal shutter speed for your photo.

Section 1 of 4:

Adjusting Your Camera & Light Meter Settings

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1
Adjust the ISO and aperture settings on your camera. Go into the settings of your camera and set it to manual mode, if it isn't in that mode already. Set your camera to your preferred ISO and aperture settings.^{[1]
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Research source} You'll need to do some experimenting with both of these settings to find the ideal settings for the photo you're trying to get.
- The ISO setting determines your camera's sensitivity to light. The higher the ISO, the more sensitivity to light. Generally, lower ISO settings produce clearer pictures while a higher ISO will cause graininess, but there are some scenarios where you'll need a higher ISO, such as when shooting a subject in motion.^{[2]
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- The aperture setting changes the size of the lens, and therefore how much light the camera lets in. This setting is described using the unit f/stops. A larger aperture number, like f/11, means a smaller lens size, and a smaller number, like f/1.4, means a larger lens size. Aperture affects your photos' depth of field and shutter speed.^{[3]
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  Research source} A large aperture creates a blurrier background, while a small one brings the background into more focus.
- When you’re using film, Bear explains that “your ISO is based off of the film, so most of the time people buy 400 ISO.”^{[4]
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  Expert Source
  
  Crystal Bear
  Professional Photographer
  
  Expert Interview. 21 January 2021.}
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Input the ISO number and aperture into your handheld light meter. For whatever ISO your camera is set at, input that number into the allocated spot on the light meter.^{[5]
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Research source} Do the same with the aperture that your camera is set at.
- A handheld light meter is also known as an incident light meter.
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3
Prepare the sensor of the light meter. Depending on what light meter you are using, you may need to twist the knob around the white dome (lumisphere) on your light meter to prepare it or slide it over a sensor. The lumisphere is what measures the light.^{[6]
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- Most lumispheres are domed, but many light meters also come with a flat sensor (called a lumidisc) that may be better for directional shots (like a portrait).
- Some domed lumispheres also recess into the light meter, which makes them function more directionally (like a lumidisc).
4
Set your light meter to the “ambient light” or “flash” mode. Most light meters have two modes: one for ambient light and one for flash. If you're going to be using the flash of your camera, set it to that mode, and if not, use the ambient setting.^{[7]
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- The flash changes how much light is hitting the subject. If you don’t account for the flash, you may end up with an overexposed photo.

Section 2 of 4:

Using a Handheld Light Meter

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Look through the viewfinder and focus on your intended subject.
If you are taking a photo of a person, have the person hold the meter up to their forehead. As Bear explains, “You can actually place the meter on somebody's forehead (or wherever you want to take the photo) and it reads the light where that person is.”^{[8]
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Expert Source

Crystal Bear
Professional Photographer

Expert Interview. 21 January 2021.} This pulls the light reading from the exact spot you want in correct exposure.
3
Aim the light meter sensor toward the source of light. The sensor (lumisphere) is the white dome-shaped or disc-shaped area of the meter. It is often on a swiveling or rotating head. Point it toward your main light source, whether that’s a window or a studio light.^{[9]
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- Most handheld light meters are incidental, meaning they measure the light falling on your subject. If your meter is reflective, that means it’s designed to measure the light reflecting off the subject. If your meter is reflective, point it at the subject (not the light source).^{[10]
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Press the measure button on the light sensor. This will measure the amount of light falling on the subject.^{[11]
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- If you're using the flash and you've set your light meter to flash mode, you'll need to hit the measure button while the camera is flashing. The meter will evaluate the degree of light from the flash and determine the correct aperture and shutter speed for the subject.^{[12]
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Read the settings on the light meter and adjust your camera to match. After hitting the measure button, most light meters will allow you to then scroll through the combinations of shutter speeds and apertures that are appropriate for the amount of light measured. Go to the settings in your camera and input the numbers provided by your light meter into your camera.^{[13]
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- According to Bear, “[the light meter reading] is just an easy way to tell the camera exactly what [settings] it needs because sometimes the internal sensors on a digital or film camera aren't 100% accurate.”^{[14]
  X
  Expert Source
  
  Crystal Bear
  Professional Photographer
  
  Expert Interview. 21 January 2021.}
- Adjust the numbers from the light meter to achieve alternative image results. Input a higher aperture (a lower f-stop number) for an image that reveals more light. A lower aperture (a higher f number) will darken the image. You can also alter the shutter speed, which allows more light in with a slower speed and increases potential blurring of any moving things in the scene.

Section 3 of 4:

Adjusting a Built-In Light Meter on SLR Cameras

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Set your camera’s ISO to match that of your film. Go into your settings and adjust the ISO to match whatever film you’re using.^{[15]
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Research source} For most film photography, this will be 400.
- Built-in light meters are also called TTL (through-the-lens) light meters.
On most cameras, pushing the shutter release button halfway down triggers the light meter to appear in the view for a few seconds (it might take you a few tries—and a few accidental photos—to get the feel for it). Double check your camera’s user manual if you can’t pull up the light meter this way.^{[16]
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Adjust the aperture and shutter speed according to the meter. Different cameras display different types of meters. Some will show a scale of negative to positive numbers with “0” being the correct amount of light. Other displays may show a green dot, a highlighted number, an arrow, or a highlighted bar to show you’ve got the right exposure. Adjust your settings until the meter shows that you've achieved the right exposure.^{[17]
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- Double check your user manual to confirm how your camera displays and fidget with the aperture and shutter speed until you have it set where you want it.
- You don’t have to set your camera to the “correct” exposure—it all depends on what effect you want. For example, having a bit more light can amke your photo brighter, while a bit less can darken it and make it look more moody.
EXPERT TIP

Crystal Bear
Professional Photographer
Crystal Bear is a Professional Photographer and the Owner of Summer Bear Photography. Crystal specializes in weddings and portraits for women. She holds a BS in Interior Design and Consumer Science from San Francisco State University. Coming from a design background, Crystal brings a sense of style and artistry to her work that brings out her client’s inner confidence, showcases their beauty both inside and out, and puts them at ease. She also specializes in using the correct lighting and branding for women entrepreneurs.

Crystal Bear
Professional Photographer

Generally speaking, you want to set your light meter in the center. I look through the lens and there's a meter at the bottom of it and there's a gauge. Since I'm a light and airy photographer, I put it a little bit to the right of center because that means it's brighter. Usually, though, you want to get the little tick mark right in the center.

Section 4 of 4:

How does a light meter work?

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Light meters show the camera settings you need based on your lighting. Basically, they measure the light entering the camera and convert that information into a reading that tells you the best aperture, shutter speed, and ISO to use to get an evenly exposed photo. They can be used for digital or film photography, but are more commonly used with film because you can’t get a preview or see what the image will look like on a screen beforehand.^{[18]
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- As Bear puts it, “It's an external device that you can actually place on somebody's forehead or wherever you want to take the photo and it reads the light where that person is. What's great about it is it tells you ‘Hey, your aperture needs to be at 2.8. Your shutter speed needs to be at 1500 and your ISO needs to be at 100,’” for example.^{[19]
  X
  Expert Source
  
  Crystal Bear
  Professional Photographer
  
  Expert Interview. 21 January 2021.}

Expert Q&A

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Question

How does a light meter work?

Crystal Bear
Professional Photographer
Crystal Bear is a Professional Photographer and the Owner of Summer Bear Photography. Crystal specializes in weddings and portraits for women. She holds a BS in Interior Design and Consumer Science from San Francisco State University. Coming from a design background, Crystal brings a sense of style and artistry to her work that brings out her client’s inner confidence, showcases their beauty both inside and out, and puts them at ease. She also specializes in using the correct lighting and branding for women entrepreneurs.

Crystal Bear

Professional Photographer

Expert Answer

A light meter is an external device that you can actually place on your subject to read the light where the subject is. The meter will tell you what your aperture, shutter speed, and ISO need to be set at. Or, you can tell your light meter what ISO you're at, and then it will tell you what your shutter speed and aperture need to be. It's an easy way to tell the camera exactly what settings to be on because sometimes the internal sensors on digital and film cameras aren't 100% accurate.

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