What is chromatic aberration? (and how to fix it)

If you’ve ever noticed strange color fringes around the edges of objects in your videos, you’re not alone. This common issue, known as chromatic aberration, can be a bit tricky to understand at first. But don’t worry, we’re here to help!

1. Understanding chromatic aberration

Chromatic aberration might sound complicated, but it’s easier to understand than you might think. Let’s break it down!

What is chromatic aberration?

So what is chromatic aberration? Simply put, chromatic aberration is an optical problem that occurs when a lens can’t focus all the colors in light to the same point. This causes those annoying color fringes—often red, blue, or green—that you sometimes see around the edges of objects in your videos.

Why does it happen?

Light is made up of different colors, each with its own wavelength. When light passes through a lens, each color bends (or refracts) by a slightly different amount. This means they don’t all meet at the same spot, creating a blur of colors around the edges. Think of it like a rainbow – the lens is splitting the colors just like a prism does.

Types of chromatic aberration

There are two main types of chromatic aberration, each caused by different factors:

1. Axial (longitudinal) chromatic aberration

• This type occurs when different colors focus at different distances along the optical axis (the line running through the center of the lens).
• You might see this as color fringing around objects that are either in front of or behind the focus point. For example, in a video, an out-of-focus background might show noticeable color fringes around bright objects.

2. Lateral (transverse) chromatic aberration

• This type happens when colors are misaligned across the image plane, especially towards the edges of the frame.
• It’s often visible as colored fringes around high-contrast edges, like a tree branch against a bright sky, where the edges appear to have a rainbow-like halo.

2. The science behind chromatic aberration

Now that we know what chromatic aberration is, let’s get a bit more scientific and dive into the fascinating world of light and lenses to understand why chromatic aberration happens.

Light and lenses

To start, it’s important to know that light is made up of different colors, each with its own wavelength. When light passes through a lens, it bends, or refracts. This bending helps the lens focus light to form a clear image. However, because each color in the light spectrum has a different wavelength, they bend by different amounts.

The role of lenses

Lenses are designed to focus light, but they can’t always bring all colors into the same focus point. High-quality lenses use special materials and designs to minimize this issue, but it’s a challenge even for the best lenses.

Practical demonstration

Want to see how light dispersion works? Here’s a simple experiment: take a glass of water and shine a flashlight through it. You’ll notice how the light splits into different colors, much like a mini-rainbow. This happens because water, like a lens, refracts different colors by different amounts.

3. Identifying chromatic aberration in video

Now that we understand what chromatic aberration is and why it happens, let’s learn how to spot it in your video footage. Identifying chromatic aberration is the first step towards correcting it and improving the quality of your videos.

Common signs of chromatic aberration

Chromatic aberration often shows up as colored fringes around the edges of objects, especially in high-contrast areas of your video. Here are some common signs to look for:

1. Color fringing: Look for red, green, blue, or purple outlines around the edges of objects. This is especially noticeable where light and dark areas meet, like the edge of a building against the sky.
2. Blurry edges: In some cases, chromatic aberration can make the edges of objects appear less sharp and more blurry.
3. Distorted colors: Colors might look unnatural or distorted, especially towards the corners of the frame.

Impact on video quality

Chromatic aberration can detract from the overall quality of your video by making it look less sharp and professional. Here’s how it affects different aspects:

• Clarity: The presence of colored fringes can make the video appear less clear, especially when viewed on high-resolution screens.
• Focus: It can give the impression that parts of your video are out of focus, even if they are not.
• Professionalism: For those aiming for professional-quality videos, noticeable chromatic aberration can be distracting and detract from the viewer’s experience.

4. Causes of chromatic aberration

Now that you know how to identify chromatic aberration in your videos, let’s dive into the various factors that cause this optical issue.

Lens design

The design and quality of your lens play a significant role in the occurrence of chromatic aberration. Here’s how:

1. Simple lens designs: Lenses with simpler designs and fewer elements are more prone to chromatic aberration. These lenses are often less expensive but lack the advanced technology needed to correct color dispersion effectively.
2. Quality of glass: Higher-quality lenses use special types of glass, such as low-dispersion (LD) or extra-low dispersion (ED) glass, which help to minimize chromatic aberration by better controlling the way light is refracted.
3. Aspherical elements: Some lenses include aspherical elements, which have a more complex shape than standard spherical lenses. These elements help to reduce various optical distortions, including chromatic aberration.

Aperture and focal length

The settings you use on your camera can also influence chromatic aberration:

1. Wide apertures: When shooting with a wide-open aperture (a low f-number), lenses can exhibit more chromatic aberration. This is because more light is entering the lens, and the differences in how colors are focused become more noticeable.
2. Long focal lengths: Zooming in or using a telephoto lens can increase the likelihood of chromatic aberration. The longer the focal length, the more pronounced the fringing can become, particularly towards the edges of the frame.

Environmental factors

The conditions in which you’re filming can also affect the visibility of chromatic aberration:

1. High-contrast scenes: Chromatic aberration is more noticeable in scenes with high contrast, such as a dark object against a bright background. The stark difference in light intensifies the appearance of color fringes.
2. Lighting conditions: Harsh lighting, such as direct sunlight, can exacerbate chromatic aberration. Shooting in softer light or using diffusers can help mitigate this effect.

Camera sensor and settings

1. High-resolution sensors: Cameras with higher-resolution sensors can reveal more detail, including optical imperfections like chromatic aberration. While these sensors can capture stunningly sharp images, they also make any lens flaws more apparent.
2. In-camera corrections: Many modern cameras offer built-in correction algorithms that automatically reduce chromatic aberration. However, relying solely on these corrections may not always be sufficient, especially in extreme cases.

5. Correcting chromatic aberration

Now that you know what chromatic aberration is and what causes it, let’s explore how to correct it. By using a combination of in-camera settings, lens choices, and post-processing techniques, you can significantly reduce or even eliminate chromatic aberration in your videos.

In-camera solutions

Modern cameras come equipped with various features designed to help minimize chromatic aberration. Here’s how you can make the most of them:

1. Built-in correction algorithms: Many cameras have built-in software that automatically detects and corrects chromatic aberration. Check your camera’s menu for settings like “Lens Aberration Correction” and make sure they are enabled.
2. Stop down the aperture: Shooting with a narrower aperture (higher f-number) can help reduce chromatic aberration. While this might limit your depth of field, it can greatly improve image quality.
3. Avoid extreme zooms: When possible, avoid using your lens at its maximum focal length. Zooming out slightly can help reduce the visibility of chromatic aberration.

Lens choices

Choosing the right lens can make a big difference in reducing chromatic aberration:

1. High-quality lenses: Invest in lenses that use low-dispersion (LD) or extra-low dispersion (ED) glass. These materials are designed to minimize the separation of colors and reduce chromatic aberration.
2. Aspherical elements: Lenses with aspherical elements are better at correcting various optical issues, including chromatic aberration. Look for lenses that include these in their design.
3. Prime lenses: Fixed focal length (prime) lenses often have better optical performance compared to zoom lenses, making them less prone to chromatic aberration.

Post-processing techniques

Even with the best equipment and settings, some chromatic aberration might still slip through. Fortunately, there are powerful tools in video editing software that can help. Here are some examples:

Adobe Premiere Pro

• Lens distortion effect: Navigate to the Effects panel, search for “Lens Distortion,” and apply it to your clip. Adjust the “Chromatic Aberration” settings to reduce the color fringing.
• Manual color correction: Use the Lumetri Color panel to manually adjust the colors and fine-tune the edges of your footage.

DaVinci Resolve

• Chromatic aberration plugin: DaVinci Resolve offers a dedicated plugin for chromatic aberration correction. Apply it to your clip and use the sliders to correct color fringing.
• Manual adjustments: Use the Color page to manually correct color fringing by adjusting the RGB channels.

HitFilm Express

• Chromatic aberration effect: Apply the Chromatic Aberration effect from the Effects panel. Use the controls to adjust the strength and radius until the fringing is minimized.

6. Using chromatic aberration for aesthetic purposes

While chromatic aberration is often considered an optical flaw, it can also be used creatively to enhance the aesthetic appeal of your videos. When applied intentionally, chromatic aberration can add a unique, artistic touch to your footage, evoking a sense of nostalgia, surrealism, or futuristic style. Here’s how you can use chromatic aberration to your advantage.

1. Creating a retro or vintage look

Chromatic aberration can mimic the imperfections of old film cameras and lenses, adding a nostalgic feel to your videos. Here’s how to achieve this effect:

• Vintage filters: Apply vintage or retro filters in your video editing software that include chromatic aberration as part of their preset.
• Subtle fringing: Add subtle color fringing to the edges of your footage to replicate the look of old films and early video cameras.

2. Enhancing surreal or sci-fi themes

For projects with a surreal or futuristic theme, chromatic aberration can enhance the otherworldly atmosphere:

• Amplify color separation: Increase the intensity of chromatic aberration to create dramatic color separation, giving your footage a distorted, dream-like quality.
• Complement digital glitches: Pair chromatic aberration with other digital effects like glitches, pixelation, or VHS tape distortion to create a cohesive sci-fi or cyberpunk aesthetic.

7. Conclusion

By understanding the causes and implementing the solutions we’ve discussed, you can significantly improve the visual quality of your videos. 

Final tips

Remember, even professional videographers encounter chromatic aberration, but with the right knowledge and tools, you can effectively manage and correct it.

1. Invest in good equipment: High-quality lenses and cameras with built-in correction features are worth the investment for reducing optical issues like chromatic aberration.
2. Be mindful of your settings: Use narrower apertures and avoid extreme zooms to minimize color fringing.
3. Edit smartly: Utilize the powerful tools available in video editing software to correct any chromatic aberration that appears in your footage.

Also remember that you can also use chromatic aberration intentionally. By doing so you can transform a technical flaw into a powerful artistic tool, adding depth, emotion, and visual intrigue to your videos.

With these insights and techniques, you’ll be well-equipped to manage chromatic aberration, whether you’re aiming for technical precision or creative expression, ensuring your videos always look their best. Happy filming!