How to Read a Light Meter

Written By Ryan Mills

How to Read a Light Meter

Light exposure is one of the elements that make a significant difference in the quality of your photography.

Many cameras come with an inbuilt meter, but professionals usually prefer a handheld meter to give attention to the light intensity and get the ideal exposure values.

Getting the correct exposure for your pictures creates brighter, well-lit images, especially at night. Reading handheld light meters gets easier once you know the basic terms and techniques.

So, if you are planning to buy one, read on to learn what a light meter is and how to use it to improve your photography.

What is a Light Meter?

Light Meter

A light meter is a photography tool that measures the quantity of light from a scene and then provides the proper settings for aperture, ISO, and shutter speed.

It gives you a detailed, well-balanced exposure where you don't get too dark shadows or too bright highlights. A light meter is also helpful if you want an optimal dynamic range.

Since much of this concerns the light source and sensor, you might need a handheld light meter to give you an empirical reading of the light in your frame.

The camera meter reading is sometimes inaccurate because it can give a reading of reflected light.

A handheld light meter, on the other hand, gives you more control and flexibility when exposing your frame.

Why are Light Meters Considered Accurate?

Why are Light Meters Considered Accurate?

A handheld light meter will give more accurate results courtesy of the incident reading. Incidental metering refers to when the handheld light meters read the amount of light that falls on a subject.

Reflected metering, on the hand, refers to the amount of light falling off the surface of an object.

Incident light reading means measuring the light falling directly on your subject. The camera, on the hand, gives you a reflective reading and meters the light that bounces off, thus the wrong exposure.

Most cameras are programmed to expose your image to "middle grey"; hence it pushes the reflected light in your images to an 18 percent gray tonality leading to even more inaccurate exposure values.

If you are shooting something very bright, for example, in an-all white gallery or portrait photography at a party, you will notice the white will reflect lots of light at your camera.

The reflective meter in your camera will assume the image is too bright and get you to underexpose the frame.

If there is anything other than the bright whites, for example, an individual dressed in black, it will try to get you to overexpose, even with the same lighting.

This is why a handheld light meter is essential for better photography.

Using Light Meters

Using Light Meters

Knowing how to use a light meter correctly will help you get properly exposed images by understanding lighting ratios and dynamic range.

Additionally, it will make your post-editing job so much easier, and you will learn how to use ambient light.

The following is a step-by-step guide on how to use a handheld meter.

Preparing Your Camera

Start by going to the settings and putting it into manual mode. Most DSLR and film cameras offer manual controls. Ensure the aperture and ISO is also set as desired.

ISO deals with how sensitive the camera is to light. The more you push your ISO numbers up, the more sensitive it will be to light.

However, avoid high ISO numbers as they reduce the image quality and cause graininess. Low ISO numbers usually give clearer images. However, when shooting moving subjects, you can push your ISO numbers up.

The aperture changes the camera lens size; thus, the quantity of light let into the camera.

'F-stop' is used to describe the aperture settings; large f-stops like 11 usually mean a small lens size. Conversely, a small f-stop, like 1.8, refers to a large lens size.

Depending on what you are shooting and what you hope to achieve with a particular frame, you should know that the aperture affects the shutter speed. So, choose the desired aperture for your scene, whether landscape or portrait photography.

Match the ISO and aperture in your light meter

Whatever ISO and aperture are set on your camera, put the same numbers in your light meter such that they have similar values.

Set up the light meter sensor

Light meters are not always the same, so you might have to adjust to a particular white dome depending on the type you might be using.

The dome is usually the sensor. You will then have to choose the appropriate mode.

Most light meters offer two modes; a mode for flash and another for ambient lighting like direct sunlight.

If you plan on using your camera flash, have it set to flash; otherwise, you would be better off at ambient. Remember to pay attention to the flash exposure.

Taking the Shot and Shutter Speed

Once you are ready, hold up the camera and, using the viewfinder rack, focus on the main subject. When doing this, keep the light meter within your reach.

You can also have someone holding the light meter at the subject's distance.

If the subject is a person, let them hold the meter up to their forehead, as this will give an accurate reading from the ideal spot.

You can now aim the external light meter sensor toward your camera. The white domed shape is the sensor, and aim it at the camera lens for the best results.

There should be a measure button on your sensor. Press it to see the quantity of light that falls on your subject.

However, if you want to use flash when capturing the subject, you might need to flash when you set the handheld light meter to flashing mode.

Doing this helps evaluate the flash degree and determine the shutter and the ideal aperture for your subject. You will then have to input the camera settings displayed by the light meter.

Most light meters will let you access the ideal shutter speeds and apertures that go with the light you have measured.

The values your light meter has provided you with regarding the aperture and shutter speed are what you are supposed to key into your camera settings.

You can play around with the numbers and ambient light to get different multiple-image exposure results.

For example, increasing the aperture value will result in an image with more light, and lowering the value will make the image darker.

Altering the shutter speed can also give mixed results. A slower speed lets more light in and gives you that blur effect when your subject moves around.

Metering Modes

Metering Modes

Depending on your camera's built-in light meter mode, there are variations if the handheld light meter measures parts of the scene or the entire scene.

These days, most cameras have a few metering modes and come in different names.

The following are some of them:

Matrix metering: this is also known as evaluative metering for Canon users. It measures the entire scene, thus creating an intelligent average, considering the various scene elements.

Center average metering: Here, there is an emphasis on the center frame, but how the entire scene is lit is also considered.

Partial metering: Popular in Canon cameras, this type focuses on a tiny portion of the center frame, which is not ideal if landscape photography is what you are after.

Spot meter: Light is measured in a small area near the central autofocus point.

All these metering modes play a massive role in whether your photo will be exposed appropriately. If spot metering happens when there is a bright sky, the photo will be all dark.

When trying to get a picture of a rock in a forested area, the image will be too bright, and the rock will be the only thing exposed.

The same case applies to wedding portrait photography. The bride's white and groom's black outfits can interfere with the exposure.

This is why knowing your way around a light meter is important.

You should also remember the dynamic range, which refers to the range of the whitest and darkest part of your frame.

The 18 percent grey will always be the optimal exposure used by most light meters.

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So, there you have it. Hopefully, you now understand more about handheld light meters and why they are essential. Operating and getting used to a light meter takes some time before you get the best possible results.

Now you can set up your key and fill lights, know how much light you need, take great quality photos with the proper exposure settings, and easily edit them.

A handheld incident light meter will ensure better results, as your camera's meter reading cannot be relied upon to give you accurate readings since it offers a reflective reading.

The best part about light meters is that you can use them with modern DSLRs and non-digital cameras.

Do not be afraid to try out new things when you are out there shooting. Experiment with your light meter as much as possible and adjust to get alternate results in your given scene.

You might learn something new and a few tricks while at it. Handheld light meters can be a game-changer for your work.

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