How do you determine the correct exposure settings with a light meter?

1 What is exposure?

Exposure is the amount of light that reaches your camera's sensor when you take a photo. It depends on three factors: aperture, shutter speed, and ISO. Aperture is the opening of your lens that controls how much light enters your camera. Shutter speed is the duration of time that your camera's shutter is open and allows light to hit your sensor. ISO is the sensitivity of your sensor to light. By adjusting these three settings, you can change the brightness and darkness of your photos.

2 Why use a light meter?

A light meter can help you find the correct exposure settings for your camera in any lighting situation. Your camera has a built-in light meter that evaluates the light reflected by your subject and the surrounding environment. However, this meter can be fooled by very bright or very dark scenes, resulting in overexposed or underexposed photos. A light meter can measure the light falling on your subject directly, without being affected by the background or the color of your subject. This way, you can get more accurate and consistent exposures.

3 Types of light meters

There are two main types of light meters: incident and spot. Incident light meters measure the light falling on your subject from the source. They have a dome-shaped diffuser that covers the sensor and captures the light from all directions. You need to place the meter close to your subject and point it towards the camera. Spot light meters measure the light reflected by a specific area of your scene. They have a narrow angle of view and a target indicator that shows you what part of the scene you are metering. You need to point the meter at your subject from your camera's position.

4 How to use a light meter

To use a light meter, you need to begin by setting your camera to manual mode and selecting the desired ISO and aperture settings. You can also set the shutter speed, but it is simpler to adjust it later based on the meter reading. Then, turn on the light meter and match the ISO and aperture settings with your camera. If you are using an incident meter, attach the diffuser to the sensor, and if you are using a spot meter, choose the spot size and angle that fits with your subject. After that, hold the light meter near your subject and point it towards your camera. If you are using an incident meter, make sure the diffuser covers the sensor completely. If you are using a spot meter, aim it at the most important part of your subject or the midtone of your scene. When you press the measure button, read the recommended shutter speed on the display and set your camera's shutter speed to match it. Take a test shot and check the histogram and LCD screen to determine if the exposure is correct. If not, adjust your shutter speed, aperture or ISO accordingly and repeat this process until you are pleased with the results.

5 Tips and tricks

If you want to use a light meter more effectively, there are certain tips and tricks to consider. For instance, use a tripod to keep your camera steady and avoid camera shake when using slow shutter speeds. You can also use an 18% gray card to meter your scene if you don't have a light meter or if you want to check your camera's meter accuracy. Additionally, exposure compensation can be used to fine-tune your exposure if you want to make your photos brighter or darker than the meter reading. Lastly, different metering modes can be used to suit different situations; matrix metering evaluates the entire scene and gives an average exposure, center-weighted metering gives more weight to the center of the frame and less to the edges, spot metering measures only a small area of the frame and ignores the rest, and partial metering measures a larger area than spot metering but still excludes the edges. By taking all of this into account, you can take full advantage of your camera's manual mode and achieve the desired creative results.

6 Here’s what else to consider

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