Light Metering Basics: Using an Incident Meter

Robert Machado

10 Dec 201811:36

Summary

TLDRIn this video, the presenter introduces incident metering, a fundamental technique in photography and videography for measuring light. The video explains how the lumisphere, an unbiased light meter, works by measuring the light falling onto its dome. The presenter demonstrates how to use the meter to set lighting ratios, crucial for creating different lighting effects. They adjust key and fill lights to achieve a two-to-one ratio, showcasing the process with a model. The video also covers the concept of f-stops, explaining how they quantify light and are used to calculate lighting ratios. The presenter's practical examples and tips make incident metering accessible, even for those unfamiliar with the concept.

Takeaways

🌟 Incident metering is a basic form of light metering that measures the light falling onto a white dome called a lumisphere.
🔍 The incident meter is unbiased as it does not consider reflectance or the color of the subject, only the amount of light falling on the dome.
📏 The meter provides an f-stop reading that indicates the amount of light available for a given scene.
💡 Adjusting the light source's intensity can change the f-stop reading, allowing for precise control over lighting ratios.
🎥 Lighting ratios are crucial in cinematography and describe how much brighter or darker one light source is compared to another.
🔧 The incident meter can be used to set up lighting ratios by measuring the key light and adjusting the fill light accordingly.
📉 When retracting the lumisphere, it can isolate a single light source, allowing for more accurate readings of that specific light.
📸 The script discusses butterfly lighting, a technique that creates a subtle shadow under the nose, often used for beauty shots.
📈 Understanding f-stops is essential for quantifying light and calculating lighting ratios; each f-stop represents a doubling or halving of light.
🤔 Memorizing the f-stop scale can be aided by recognizing that each stop is either double or half the previous amount of light.
🎬 The incident meter is a practical tool for filmmakers to set lighting ratios and ensure consistent lighting across different shots.

Q & A

What is incident metering?
-Incident metering is a method of measuring light that involves using a device, like a lumisphere, to measure the amount of light falling onto its dome. It is unbiased because it doesn't care about the subject's reflectance or color; it only measures the light that reaches the meter.
What is a lumisphere?
-A lumisphere is a small white dome used in incident light meters to measure the light falling onto it. It is designed to provide an unbiased measurement of light.
How does incident metering help in setting lighting ratios?
-Incident metering helps in setting lighting ratios by allowing the user to measure the amount of light falling on the subject and then adjust the light sources to achieve the desired ratio. For example, if the key light measures at f/2.8 and the fill light at f/2, that's a 2:1 ratio, with the key light being twice as bright as the fill.
What is an f-stop and how does it relate to light measurement?
-An f-stop is a unit used in photography to describe the amount of light that reaches the camera sensor. Each f-stop represents a halving or doubling of light, with a lower f-number allowing more light and a higher f-number allowing less light.
How can you remember the relationship between f-stops and the amount of light?
-The relationship between f-stops and light can be remembered by knowing that each stop represents a halving or doubling of light. For example, going from f/2 to f/4 halves the light, while going from f/4 to f/2 doubles it. The scale can be memorized by starting with f/1 and f/1.4 and then doubling the previous number to get the next f-stop.
What is the difference between a key light and a fill light?
-The key light is the primary light source that defines the subject's appearance and establishes the overall lighting mood. The fill light is a secondary light source used to soften shadows created by the key light, providing more even lighting.
What is a lighting ratio and why is it important?
-A lighting ratio is the relative measurement of the brightness between the key light and the fill light. It is important because it helps to create depth and dimension in a scene, as well as to set the mood and style of the lighting.
How can you adjust the incident meter to measure a single light source?
-To measure a single light source with an incident meter, you can retract the dome and cover the head of the meter, then point it towards the light source you want to measure. This isolates the light from other sources.
What is butterfly lighting and how is it achieved?
-Butterfly lighting, also known as Paramount lighting, is a style where the key light is positioned high and slightly in front of the subject, casting a shadow under the nose that resembles the outline of a butterfly. It is typically achieved with a soft light source and is flattering as it creates a soft shadow and even lighting.
How can you use incident metering to create menacing or dramatic lighting?
-To create menacing or dramatic lighting with incident metering, you can turn off the key light and measure the light levels with the fill light only. This can create a darker, more dramatic scene by reducing the overall light and increasing the contrast.
What is the significance of the number 5 in the context of stops and light measurement?
-In the context of stops and light measurement, a difference of 5 stops means that one light source is either 32 times brighter or 32 times dimmer than another. This is because each stop represents a doubling or halving of light, and 2 raised to the power of 5 equals 32.

Outlines

00:00

📸 Introduction to Incident Metering

The speaker introduces incident metering, explaining that it is the most basic form of light metering. They describe the lumisphere, a small white dome that measures light falling onto it, providing an unbiased reading of light intensity. The speaker demonstrates how to use the incident meter by taking readings in different lighting conditions and adjusting the light sources accordingly. They also discuss how incident meters can be used to set lighting ratios, which is the relative brightness or darkness of lights compared to one another. The concept of f-stops is introduced as a way to quantify light, with a detailed explanation of how changes in f-stops relate to doubling or halving the amount of light.

05:01

💡 Understanding Lighting Ratios and F-Stops

The speaker elaborates on lighting ratios, explaining how they determine the relative brightness of key and fill lights. They provide examples of different lighting ratios and how they affect the look of a subject in a scene. The concept of butterfly lighting is introduced, which is a type of lighting that creates a subtle shadow under the nose, often used in beauty or portrait photography. The speaker demonstrates how to adjust the fill light to achieve a flat but flattering look. They also discuss the importance of memorizing the f-stop scale and provide a method for doing so by counting backwards from higher f-stops to lower ones.

10:02

🎥 Practical Applications of Incident Metering

The speaker shares practical tips on using incident metering, such as turning off lights to isolate a single light source for measurement. They demonstrate how to adjust the light levels using a dimmer and explain the concept of stops in relation to light intensity. The speaker also addresses the difficulty some people have with memorizing f-stop values and suggests using a light meter as an alternative. They conclude by inviting viewers to ask questions and share their thoughts in the comments.

Mindmap

Keywords

💡Incident Metering

Incident metering is a method of measuring light that involves pointing a light meter at the subject to determine the amount of light falling on them. In the video, the instructor uses a device called a 'lumisphere' to demonstrate incident metering, which is crucial for understanding how much light is available for a shot. This technique is fundamental to achieving the desired exposure and is used to set up lighting ratios.

💡Lumisphere

The lumisphere is a specific type of light meter that measures incident light. It is described as a 'little white dome' in the script. The device is unbiased as it measures the light falling onto its dome without considering the subject's reflectance or color. The instructor uses the lumisphere to take readings and adjust the lighting setup, emphasizing its importance in achieving balanced lighting.

💡F-stop

An f-stop is a term used in photography and videography to describe the aperture setting on a camera, which controls the amount of light that enters the camera. The script mentions that an f-stop is a measure of light quantity, with each stop representing a doubling or halving of light. The instructor uses f-stop values to communicate the lighting levels and to adjust the camera settings accordingly.

💡Lighting Ratios

Lighting ratios refer to the relative brightness between different light sources in a scene. The video discusses how the instructor sets up lighting ratios using the incident meter. For example, a key light might be set to an f/2.8, while a fill light is adjusted to an f/2, creating a 2:1 ratio, meaning the key light is twice as bright as the fill light. This concept is essential for creating depth and mood in visual storytelling.

💡Key Light

The key light is the primary light source in a scene, responsible for illuminating the subject and providing the main illumination. In the script, the key light is set above the subject, and its intensity is measured using the lumisphere. The instructor adjusts the key light to create a specific look and to establish the desired lighting ratio.

💡Fill Light

Fill light is used to soften shadows created by the key light, providing a more even illumination. The video script describes how the instructor turns on a fill light and adjusts its intensity to achieve a 2:1 ratio with the key light. The fill light helps to create a more flattering and balanced look on the subject.

💡Butterfly Lighting

Butterfly lighting, also known as Paramount lighting, is a classic lighting setup where the key light is placed high and slightly in front of the subject, casting a shadow under the nose that resembles the outline of a butterfly. The script mentions this technique as a form of beauty lighting, which is flattering and even, making it suitable for portraiture.

💡Reflectance

Reflectance is the property of a surface that determines how much light it reflects. The lumisphere, as mentioned in the video, is unbiased and does not care about reflectance, meaning it measures the light falling on it without being influenced by the color or shininess of the subject. This is important for achieving accurate light readings regardless of the subject's characteristics.

💡Dimmer

A dimmer is a device used to control the intensity of light emitted by a light source. In the script, the instructor uses a dimmer to adjust the brightness of the key light and fill light. Dimmers are essential tools in lighting setups as they allow for precise control over the amount of light reaching the subject.

💡ND Filter

An ND (Neutral Density) filter is a type of optical filter used to reduce the amount of light entering the camera without affecting the color. The script briefly mentions adjusting an ND filter when changing the lighting setup. ND filters are used to control exposure, especially in situations where a wide aperture is desired but too much light is present.

💡Beauty Lighting

Beauty lighting is a specific style of lighting that is designed to enhance the subject's appearance, often used in fashion, portrait, and beauty photography. The video script describes butterfly lighting as a form of beauty lighting because it creates soft, even light that is flattering to the subject's features.

Highlights

Introduction to incident metering, the basic form of light metering.

Explanation of the lumisphere, a device that measures light falling onto its dome.

Demonstration of taking a light reading with an incident meter.

Discussion on the unbiased nature of incident metering.

How to set lighting ratios using an incident meter.

Explanation of lighting ratios and their significance in photography and videography.

Practical demonstration of adjusting key light using a Kino dimmer.

Use of the incident meter to measure the intensity of a single light source.

Adjusting fill light to achieve a specific lighting ratio.

The concept of f-stops and how they quantify light.

Explanation of how f-stops relate to the amount of light.

Practical demonstration of adjusting f-stops to achieve different lighting effects.

Discussion on the concept of butterfly lighting and its origin.

Explanation of how butterfly lighting creates a flattering effect.

Practical demonstration of adjusting fill light to achieve a flat and flattering look.

Advice on memorizing the f-stop scale for quick calculations.

Practical tips for using incident metering to set up lighting ratios.

Discussion on the importance of understanding stops for lighting calculations.