Chromatic Aberration: What is it and How to Avoid it
Chromatic aberration is a common optical problem of a photographic camera, also known as “color fringing” or “purple fringing”. This occurs when a lens is either unable to bring all wavelengths of color to the same focal plane. It can happen too when wavelengths of color are focused at different positions in the focal plane.
In this post, you learn what is it and when appears. But also how to avoid it with simple tips and how to fix it in Lightroom or Camera Raw in 5 easy steps.
What is chromatic aberration?
Trying to explain simply, is a phenomenon in which light rays pass through a lens focus, and the colors incorrectly refract by the lens at the sensor. It results in a mismatch at the sensor, where the colors make a wrong combination.
Remember that the sensor of your camera (or focal plane), is where your sensor’s point should collect all ray lights. This problem appears, when the construction of your lens, or/and any special focal length of the lens, and even the aperture that you’ve used cause the colors (or wavelengths) to arrive at different points to the final destination that is your sensor.
If this happens, your final photo will show a telltale color fringing around the edges in your photograph. This happens more often than we can think, this way almost all photographers recommend always activating the option in Lightroom or Camera Raw to remove it.
But if we can avoid this problem at the moment of taking pics, the result will be much better and we will avoid problems in the future. At the end of this post, you will find a tutorial on how to fix it in Photoshop & Lightroom, but continue reading to avoid this step for every single photo you will take.
There are two types of chromatic aberration, lateral (or transverse) and longitudinal chromatic aberration. The first one (lateral chromatic aberration) occurs when different wavelengths of light are focused at different positions on the surface of a camera’s image sensor. The second type of chromatic aberration, transverse chromatic aberration or axial chromatic aberration occurs when the different wavelengths of colored light are focused at different distances from the surface of the image sensor.
Why does chromatic aberration occur?
Even with the best camera, chromatic aberration can happen because your lens acts as a prism. Thanks to Pink Floyd, the triangle of how light reacts when passing through the glass. In our lens, the light must pass different glasses to come to our sensor. So it will depend on the properties and quality of the glasses, that chromatic aberration occurs.
Light is made of various wavelengths (colors), this way we need that our camera sensor receives at the same point all wavelengths. At the moment that our glass separates these wavelengths, the rays not will hit the exact point.
Can sound easy, but remember that all the wavelengths will be crossing our lens at the same time. And every one of these rays will be passing from a different area of our lens, which means that can be affecting different from our lens.
This is one of the points, that make your lens the most important gear of your photo equipment. Your lens must be able to correct & align all these rays, and any small fault here will ruin our photo. This way, all manufacturers spend millions to develop the best possible lens.
The engineering inside your lens includes up to 16 lens elements designed to correct the light journey between your lens and the sensor of your camera.
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It’s easy to understand, that behind all these elements can appear defects. These errors can be directly in the design of the lens or can appear according to specific conditions. At the moment that one of these elements has a defect in the glass, your photos will be showing this type of aberration.
All this doesn’t mean, that you need to get a pro-level lens to avoid it. All lenses suffer in one way or another chromatic aberration. The key is to control when your lens is showing it, in which situation appears if your lens is okay, or repair your lens if you have a hit and start to appear in your pics.
How to avoid chromatic aberration
There are several tips to avoid chromatic aberration, but in most cases, you can easily remove it in post-processing by simply shooting in RAW. But before knowing how to fix chromatic aberration in post-processing, let’s see some tips during the moment of capturing your photo.
The best way to avoid this problem is following these easy steps, so you will be saving time and improving the quality of your photos directly in the camera.
Even if you have a camera that has problems with it, these tips can help you to reduce the visibility of this mistake. Following these strategies, you will minify the effect in your photos and can save you a visit to the technical service for a problem with a hard fix.
Avoid high contrast scenes
For travel photography, it’s one of the best tips. High contrast scenes will make your lens suffer more to control the wavelengths and chromatic aberration will easily appear. Try to avoid the scenes where you have high contrast lights and wait for better light conditions.
Another solution is to measure the light for shadows or lights, and don’t try to capture all the dynamic range. For example, if you are trying to capture a detail of the japan sakura.
If you are a landscape photographer, you will love to shoot directly to a bright sunrise. This is one of the situations when can appear. In this particular case, one solution is to reframe your composition or try to reduce the effect with the bracketing technique.
After your shoot in a high contrast scene, even following these steps, you will need to work in the RAW file to reduce the effect of the chromatic aberration. But at least, you will get your shot cleaner, and will be easy to reduce the effect.
Check your focal lengths
The chromatic aberration usually appears in the extreme at the shorter and longer focal range. This way, it’s great to have a wide lens to have the possibility to correct this problem in the exterior of your photos. But, most of the lenses will exhibit some kind of aberration in these areas. So be careful always to understand how your lens works.
One good option to avoid this problem is to make a panorama of your landscape. In this way, you will avoid the problem in the exterior of your focal range, but you will be able to keep the composition as you have in mind after merging the photos in post-production.
Stop down your aperture
Another good tip if you have problems with it, is to don’t use apertures as f22. This way, you will reduce the time that the light is crossing your lens, reducing also the effect. In this case, remember that you will need to readapt your shutter speed or increase the ISO to compensate for the loss of light.
Reframe your subject to the center of the image
As we explain before, chromatic aberrations usually occur more often at the exterior of your image. It happens as the curvature of the lens creates the barrel effect, and it affect also to how the light enters your lens.
So, one good tip, especially for travel photography, is to move your subject to the center of your composition. In this way, you will avoid or reduce the issue not only with chromatic aberration but also with other defects of your lens.
If we think, what is the end result of your images, you will realize that most of your images finish in social media where resolutions are not as high as your RAW file. It means, that you can crop your image in post-production to correct the composition you had in mind at the moment of the shoot.
Now that you understand how it works, you will be able to avoid and reduce this common problem for landscape & travel photographers. Anyway, if you want to fix it complete here it’s a complete tutorial to fix it in post-production.
How to fix Chromatic Aberration in Photoshop & Lightroom
In 5 easy steps, you can learn how to fix it in Adobe Lightroom. The steps for Camera Raw are the same, so even if you edit a photo in Photoshop, you can easily remove the chromatic aberration on Photoshop.
Step 1. In Lightroom zoom in on a part of your image where it’s more visible.
Step 2. Go to the Develop mode and click on the Lens Correction panel.
Step 3. Turn it on the ‘Remove Chromatic Aberrations’ checkbox. Then select your ‘Lens profile’ if Lightroom doesn’t choose or select your specific model.
Once you complete these steps, zoom on your image and look if the problem is fixed. This simple process will correct most images. You can also use the same process in Camera Raw before opening your image in Photoshop.
If still, some chromatic aberration is visible in your image after that, move to the next steps.
Step 4. Click on the ‘Manual’ tab in the ‘Lens Correction’ panel.
Step 5. Look again in your image and check the remaining color. If for example, you see a purple line around the edges, increase the ‘Amount’ slider of ‘Purple Hue’ till the fringe disappears. Follow the same steps for the ‘Green Hue’ in case the line around the edges is green.
Usually, only these sliders will be needed to eliminate fringing. But, if you need to make additional adjustments, you can use the range of each color (Purple and Green). Using these sliders will help you to increase the range of color to correct.
We hope that this post helps you to understand what is chromatic aberration, but also how to avoid and how to fix it. If you have any doubts about it, you can write a comment below and we will be glad to help you.
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