Let's Learn Light! Studio Lighting 101: Main Light vs Fill Light

In this insightful article, we will thoroughly explore the delicate dance between your main light and fill light. Understanding this dynamic relationship is not only vital for setting up your studio lighting plan but also empowers you to create the perfect mood, contrast, and visual appeal in your images. Unlock the secrets of professional lighting techniques and take your photography to new heights!

The main light and fill-in light are essential components of the lighting setup in photography and videography. They serve different purposes and work together to create a well-balanced and visually appealing scene.

Main Light: The main light, also known as the key light, is the primary light source in a lighting setup. Its main purpose is to provide the primary illumination on the subject and define the overall look and mood of the scene. The main light is usually positioned to one side of the subject, creating highlights and shadows that add depth and dimension to the image.

Fill-in Light: The fill-in light, also known as the fill light, complements the main light by reducing the contrast created by the main light's shadows. Its primary role is to soften the shadows and provide a gentle, even illumination to the areas that would otherwise be in shadow due to the main light.

Studio Lighting 101: Exploring the use of a main light and fill-in light

Today's photography setup involves these two essential components: a main light and a fill-in light, each serving a specific purpose in achieving the desired lighting effects. Let's dive into the details of our setup and how we plan to experiment with the fill-in light's power settings to observe and understand the variations it brings to the scene.

1. Main Light Setup: The main light is positioned on the left-hand side (from the Photographer's point of view) and is set at its maximum power, which is denoted as "1/1" or full power. At this setting, the main light emits light at 100% of its capacity, producing a strong and impactful illumination on the subject. This powerful burst of light from the main light helps to create a dominant light source that shapes the overall mood and emphasizes certain aspects of the subject.

    

2. Fill-in Light Setup: The fill-in light is placed on the right-hand side (from the photographer's POV). The purpose of the fill-in light is to balance the shadows created by the main light and to reduce harsh contrast in the scene. It serves to "fill in" the shadows, resulting in a more even and pleasing illumination of the subject. The initial power setting for the fill-in light is "1/64," which corresponds to an output of 1.56% of the full power.

    

Now, the real experimentation begins. We intend to explore the impact of incremental power adjustments on the fill-in light. Starting from 1/64, we plan to increase the power setting one full stop at a time. A full stop, in this context, refers to doubling or halving the light's intensity.

Our camera settings are 1/125, f8.0, and ISO100.

It should be noted that these settings are relative to many factors and variables, such as the equipment used, camera settings, and the positioning of the light sources.

Studio Flash Settings: 

As a helpful reference, the table below showcases the various flash settings and their corresponding percentages relative to the full power of the flash:

The table outlines the incremental steps at which the flash can be adjusted, expressed as fractions of full power. Each setting corresponds to a specific percentage of the flash's maximum capacity.

When using the flash at full power (1/1), it operates at 100% of its total capability, providing the brightest and most intense burst of light. By reducing the power to 1/2, the flash emits light at half its full strength, resulting in a 50% output. Similarly, at 1/4 power, the flash emits only a quarter of its total light, equating to 25% of the full power.

As we delve into lower power settings, the adjustments become more nuanced. At 1/8 power, the flash emits a mere one-eighth of its maximum capacity, amounting to 12.50% of full power. Further decreasing the output to 1/16 power results in a 6.25% intensity, while 1/32 power delivers a mere 3.13% of the flash's full potential.

It should be noted, that some flashes, like the Godox range of PRO strobes, are capable of going even lower than 1/64, all the way down to 1/256, providing the tiniest amount of light when necessary. 

Here are the results: 

The results above demonstrate how the interplay between the main light and fill-in light significantly influences an image's mood, contrast, and depth.

Main Light Power: 1/1

Fill Light Power: 1/64

Main Light Power: 1/1

Fill Light Power: 1/32

Main Light Power: 1/1

Fill Light Power: 1/16

Main Light Power: 1/1

Fill Light Power: 1/8

Main Light Power: 1/1

Fill Light Power: 1/4

Main Light Power: 1/1

Fill Light Power: 1/2

Main Light Power: 1/1

Fill Light Power: 1/1

Main Light & Fill Light Ratios

The main light-fill light ratio refers to the relationship between the intensity of the main light and the fill light used in a photography or videography lighting setup. It is a crucial factor in determining the overall look and mood of the photograph or video.

The ratio is expressed in numerical terms, such as 1:1, 2:1, 3:1, etc. The first number represents the intensity of the main light, and the second number represents the intensity of the fill light. For example, a 1:1 ratio means that the main light and fill light have equal intensity, while a 2:1 ratio indicates that the main light is twice as bright as the fill light.

Please be aware that the intensity of light refers to the amount of light falling on your subject, rather than the settings on the flash unit itself. To accurately measure the differences between your main light and fill-in light, you must use a light meter. This tool allows you to measure the light intensity independently from both of these light sources.

The impact of the main light-fill light ratio on a photograph can be summarized as follows:

1. Contrast and Mood: A higher main light-fill light ratio, such as 2:1 or 3:1, creates more contrast in the scene. This means that there will be stronger highlights and shadows, resulting in a more dramatic and moody image. On the other hand, a lower ratio, like 1:1, produces a softer and more even illumination, reducing contrast and creating a lighter, more natural feel.

2. Depth and Dimension: A higher main light-fill light ratio enhances the sense of depth and dimension in the photograph. Stronger shadows give the subject more three-dimensional form, making it stand out from the background. In contrast, a lower ratio reduces the shadows, potentially making the scene look flatter and less dynamic.

3. Emphasis on the Subject: A higher main light-fill light ratio can draw more attention to the subject by creating more pronounced highlights on it. This is particularly useful when you want to make the subject stand out prominently in the composition. Conversely, a lower ratio can reduce the emphasis on the subject, allowing other elements in the scene to share the spotlight.

4. Mood and Style: The choice of main light-fill light ratio can significantly impact the overall mood and style of the photograph. A higher ratio with strong contrasts is often used in dramatic or artistic photography, while a lower ratio is more commonly seen in soft, flattering portrait lighting.

5. Control and Creativity: Adjusting the main light-fill light ratio provides photographers and videographers with creative control over the lighting setup. By modifying the intensity of each light, they can achieve various lighting effects and craft unique visual stories.

Ultimately, the main light-fill light ratio is a powerful tool in the hands of photographers and videographers, allowing them to shape the scene's aesthetics, control the mood, and direct the viewer's attention to create impactful and visually compelling images and videos.

Below is a table detailing different main-fill light ratios and their respective applications in photography and videography:

Applications:

1:1 Ratio: Equal intensity between the main light and fill light.

• Portraits: Provides soft and flattering lighting, reducing harsh shadows on the subject's face.
• Still Life: Offers balanced illumination with minimal contrast for capturing intricate details.

2:1 Ratio: The main light is twice as intense as the fill light.

• Portraits: Creates moderate contrast, adding depth and dimension to the subject's features.
• Fashion Photography: Enhances the subject's contours while maintaining a pleasing balance of shadows.

3:1 Ratio: The main light is three times as intense as the fill light.

• Dramatic Portraits: Produces higher contrast and deeper shadows, ideal for creating bold and intense mood.
• Artistic Photography: Adds a strong sense of drama and dynamic lighting to the scene.

4:1 Ratio: The main light is four times as intense as the fill light. Applications:

• High-Contrast Portraits: Results in a striking interplay of highlights and shadows, creating a more expressive and edgy look.
• Creative Lighting: Suitable for experimenting with bold lighting effects and artistic compositions.

8:1 Ratio: The main light is eight times as intense as the fill light.

• Special Creative Effects: Used for highly stylized and artistic shots, where the lighting itself becomes a prominent element.
• Experimental Photography: Allows for unique and unconventional lighting setups, providing a distinct visual impact.

Remember, these ratios serve as starting points, and actual intensity values can be adjusted based on the specific scene, subject, and artistic vision. Understanding how to control the main light and fill light ratio empowers photographers and videographers to craft compelling and visually captivating images that align with their creative intentions.

In conclusion, this insightful article has thoroughly explored the delicate dance between the main light and fill light in photography and videography. Understanding this dynamic relationship is vital for setting up your studio lighting plan and unleashing your creative potential to create the perfect mood, contrast, and visual appeal in your images. By unlocking the secrets of professional lighting techniques, you can elevate your photography to new heights and craft impactful and visually compelling visuals. Embrace the power of the main light-fill light ratio, experiment with different settings, and discover the art of shaping scenes to captivate your audience with captivating imagery.