What is Chromatic Aberration
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Chromatic Aberration: What It Is, How to Remove It, and More

Chromatic aberration is a result of a lens’s inability to correctly scatter all the coloured wavelengths at the same location. It’s caused by a lens having trouble focusing different wavelengths of light at the same point. In other words, one colour of light either focuses in front of another part of the image or behind it. There are two types of chromatic aberration: radial and lateral. Lateral Chromatic Aberration appears as an unnatural purple or blue halo around the edges of objects in an image and is particularly visible when shooting subjects with high contrast. It appears at different degrees in every photograph and can be influenced by several factors such as aperture type, focal length, and distance from subject.

Did you notice the aberration in the feature Image? 

Table of Contents

What is Chromatic Aberration?

Chromatic aberration, commonly referred to as colour fringing, is a colour displacement that leaves an undesirable coloured border around the edges of objects in photographs.

It happens when a lens either cannot focus all colour wavelengths onto a single reference spot or when various colour wavelengths are concentrated at different locations on the focal plane. Lens dispersion, which results from different hues of light entering a lens at various speeds, is what causes chromatic aberration. As a result, particularly in high-contrast settings, the image may appear blurry or distinguishable coloured edges may emerge around objects.

It is further separated into two parts: Lateral or Transvers and Axial or Radial.

Example of what is Chromatic Aberration

What is Transverse or Lateral Chromatic Aberration?

Lateral chromatic aberration is a type of chromatic aberration that causes a slight colour fringe along the edges of objects in a photograph, especially where there is high contrast between the object and its background. It is caused by the failure of the lens to focus all wavelengths of light at the same point.

The degree of lateral chromatic aberration can be quantified in terms of the focus shift that is required to make the fringe disappear. A lens with low lateral chromatic aberration will require a small focus shift to correct the aberration, while a lens with high lateral chromatic aberration will require a large focus shift to eliminate the aberration. Light that is incident at an angle causes Lateral Chromatic Aberration. Then, despite the foci not being situated along the optical axis, all colours are in emphasis in the same plane. Due to the dependence of the magnification on the wavelength, this type of aberration results in fringes around structures of vivid colour rather than coloured regions.

How to Fix Lateral Chromatic Aberration

Avoid high-contrast scene and shot

Chromatic aberration is particularly obvious when shooting situations with high contrast. Particularly problematic photographs are those with darker objects, or intensely backlit objects. Contrast cannot be easily avoided in-camera. You frequently are forced to alter your content as a result. Consider altering your backdrop so that it more closely resembles the colours of your object, or just wait for improved illumination. Shoot in RAW and prepare to do some post-production adjustments if you absolutely must capture the photo.

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Switch to higher Aperture Value

Stopping down is yet another technique that anybody can use and may lessen chromatic aberration. Use an aperture that is one or two stops larger than your lens’ maximum. This is due to the fact that the best lenses—like the Canon 17-40mm—are designed to minimize the splitting of light as it travels through the glass components. Consider purchasing lenses with low-dispersion components. These are made to drastically cut down colour fringing.

Try Using a Different Camera Lens

Another way to reduce chromatic aberration is to use a different lens, like a macro lens, which is designed to focus on small, detailed subjects. While you can’t completely avoid chromatic aberration, changing your lens can help reduce it. If you’re shooting with a zoom lens, try zooming out as far as you can and then backing up as far as you can. This will reduce the amount of chromatic aberration in your image since the zoom lens was designed for closer subjects. You can also try switching to a prime lens, especially a wide-angle lens, which will give you a shallow depth of field and help blur out any chromatic aberration.

You can use specially designed lens which is called a the achromatic lens. The optical spectrum’s bands at both extremities are subject to an achromatic adjustment. Curved crown glass and concave flint glass are both components of an achromatic optic. An “achromatic doublet” is produced as a result of this arrangement, which can lessen the impacts of refractive error.

What is chromatic aberration example with lens

What is Radial or Axial or Longitudinal Chromatic Aberration?

Radial chromatic aberration is a type of chromatic aberration that appears as a blurred or smeared area in the center of the image. It is caused by the inability of a lens to focus all wavelengths of light at the same point. The degree of radial chromatic aberration can be quantified in terms of the percentage of the image that is blurred. A lens with low radial chromatic aberration will blur a small percentage of the image, while a lens with high radial chromatic aberration will blur a large percentage of the image.

Direct incident light is the reason for Radial Chromatic Aberration. The distinct hues’ foci are located at various locations along the optical axis in the longitudinal direction. Due to a limitation in the ability to display all three colours in sharp focus, longitudinal chromatic aberration causes coloured patches to appear in the photographs.

Coloured margins can result from both aberrations. Yet, lateral refracted light mainly affects tangential features, but longitudinal refracted light produces colorful edges all around structures. Additionally, Radial Chromatic Aberration can happen at any place on the picture, in contrast to lateral chromatic aberration, which gets worse as it moves to the extremities of the frame.

How to Fix Radial Chromatic Aberration

Lens Corrections

You can also try lens correction for your camera. Use low-dispersion glasses for your lenses, particularly if they include fluorite. They effectively lessen image distortion. Lens adjustments assist in removing flaws visible in almost all camera images. These might be a darkening around the frame’s corners, lines that would normally be straight seeming curled, or colour fringes close to edge details. Even while they are frequently not seen in the original image, the advantages of having them removed nearly always are. Lens corrections, however, can have the ability to degrade photographs if not done correctly, and based on the issue, certain flaws may even be advantageous.

Subject Positioning and Shutter

Another option is to attempt positioning your topic in the middle of the frame. Latitudinal chromatic aberration is one sort of colour fringing that only appears on the frame’s borders. You may minimize the impact that chromatic aberration has on your shot by placing your main subject in the middle of the frame. Stopping down your aperture will help because slower lenses are often less prone to longitudinal refractive error than faster lenses. This might lessen it or resolve it entirely. Remember that you may adjust your shutter speed, increase your ISO, add a light or other flashlight, or other methods to account for light as you stop down.

Use a Preset

If all else fails, try using a preset. There are a lot of free and paid presets for Photoshop that can help you reduce chromatic aberration. The “Warming Filter” will help reduce the blue or purple hue from the edges of your image, while the “Cooling Filter” will reduce the orange or yellow hue. The “Warmth” and “Coolness” filters can be used to adjust the hue of your entire photo. The “Neutral Colour Replacement” filter can be used to paint over an entire image with a neutral grey hue that will help reduce all of the chromatic aberrations in your image. You can also try using the “Vibrance” and “Saturation” sliders to reduce the orange or yellow hue in your photo.

Editing Software: An effective solution

Chromatic aberration can be fixed to a large extent with the help of an editing tool. Adobe Lightroom is a light and powerful editing platform. The Lens Correction Function in Photoshop is the most straightforward tool for chromatic aberration reduction. Chromatic aberration may be corrected manually or automatically using this filter. According on the colours you wish to eliminate, use the various sliders. Let’s see how we can use Lightroom to remove chromatic aberration. It can be done using two steps.

Option 1

Select the “Remove Chromatic Aberration” checkbox in the Lens Correction Panel under Profile section. Lightroom will automatically adjust the hues to try and correct any chromatic aberration in the image.

Option 2

Click on the Manual section to open an advanced correction panel. Now pick the eyedropper tool and select the area on the image where you can see the issue. You will see the Purple and Green Hue sliders below the eyedropper tool now. When you increase the Quantity adjusters, Lightroom will eliminate any leftover straying. The Purple Hue and Green Hue settings allow you to precisely target the fringing hues.

What if Lightroom Cannot fix?

Well, there is always Photoshop.

Step 1: Launch Photoshop and open the chosen image.

Step 2: Right-click on your background layer and select Duplicate Layer from the menu to create a duplicate layer. The Chromatic Aberration Layer will now be given a new name. This will make it simple for you to recall and return to your earlier edits after you are finished.

Step 3: Select your Chromatic Aberration Layer, then click the Filter option in the menu bar. Then pick Gaussian Blur after choosing Blur.

Step 4: Determine your radius in the Gaussian Blur window based on the degree of chromatic aberration in your image. You may start with a radius of 5 pixels, for instance.

Step 5: The blend mode menu can be found at the top of your layer panel. Normal would be the default setting. The Chromatic Aberration Layer’s blending mode should be changed to Colour. You can desaturate the layer by doing this.

Step 6: Apply a mask to your Chromatic Aberration Layer at this point to prevent the effect of chromatic aberration removal from affecting the entire image. By clicking Layer, choosing Layer Mask, and then selecting Hide All, you may accomplish this. This will make your chosen layer invisible.

Step 7: Next, change the foreground colour to white and select a soft-edged brush from the tools panel.

Step 8: Select the brush’s opacity based on the amount of chromatic aberration present in your image, and then paint over any places where colour fringing is present. You can reverse your actions at a later time by changing the foreground colour to black. If it helps you to envision, you can also paint over the sections you don’t want to be affected by the modifications.

Step 9: When finished, apply the layer mask by selecting Apply The Mask with the right-click menu.

Step 10: Next, select Flatten The Image from the context menu by right-clicking on the Chromatic Aberration Layer. You’ll see that this eliminates chromatic aberration in your image.

Conclusion

In conclusion, chromatic aberration, or colour fringing, is a common issue in photography that occurs when the lens cannot focus all colours of the spectrum onto the same plane. This results in a misalignment of colours, causing them to appear as fringes or halos around the edges of the subject. It can be caused by a variety of factors, including the design of the lens, the focal length, and the aperture.
Chromatic aberration is most noticeable in high-contrast areas and can be problematic when shooting with a wide aperture. To mitigate chromatic aberration, we can use lens corrections in post-processing software, choose lenses that are specifically designed to minimize chromatic aberration.

Frequently Asked Questions

All spherical lenses include chromatic aberration, also known as the chromatic longitudinal distortion.

Chromatic aberration, a frequent issue with telescopes, happens when colours are improperly deflected by the lens, causing a mismatch where the colours do not mix as they ought to at the focal point.

 Chromatic aberration distorts the picture, degrading its overall quality. The majority of the time, however, this blurring is absolutely unneeded and just helps to degrade the picture quality and obscure details. It is only beneficial in a small number of specific situations.

Spherical aberration happens when a lens or mirror’s curvature leads rays travelling on the edges to focus at a distant location than those falling in the Centre. The resulting photographs seem hazy as a result.

The typical amount of longitudinal chromatic aberration in the human eye is estimated to be 1.75 D across 420 and 660 nm

The best way to show how light dispersion causes chromatic aberration is with a prism. The division of photons into its many wavelengths is known as dispersion. At the borders, light that travels between two materials will be distorted or refracted, causing chromatic aberration.

Combining a strong lens composed of low-dispersion glass with a weaker optic made of high dispersion glass would reduce chromatic aberration. One describes such a mixture as achromatic.

When looking through the optical centre of the lens, chromatic aberration has no impact on vision since the optical spectrum’s red, blue, and all other wavelengths are layered on top of one another to produce the picture.

When light rays are not parallel to the optical axis of a lens, this is known as Coma. Points of light may appear stretched out or “feathered” at the edges.

A variation of an aberration is distortion. This aberration happens when the lens’s focal lengths vary when the lens is moved away from its main axis. The otherwise straight item becomes warped. The following are typical examples of these kinds of aberrations:

  • Barrel
  • Pincushion

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