Chromatic Aberration:
what is it and should I use it or avoid it?

Chromatic aberration, also known as colour fringing, is a colour distortion that will leave visible imperfections on your photographs. Generally, it creates an outline of unwanted colour along the edges of objects in a photograph.

Often, chromatic aberration appears along metallic surfaces or where there is a high contrast between light and dark objects – such as a black wall in front of a bright blue sky. Each type of aberration causes different colours of outlines along an object’s edge.

It’s because it often occurs at the edge of an image and objects within it that it’s known as colour fringing.

“Looking back through old photos, I notice fringing and I am horrified that it’s been in there the entire time.”
Nick Mendez, photographer and filmmaker

Chromatic aberration relates to your camera and more specifically its lens and how it processes light. We’ll talk more about this in the next section. It’s also important to know there are two main types of chromatic aberration:

• Longitudinal – occurs when the lens fails to bring different wavelengths of colour to a fixed focal point
• Lateral – occurs when different wavelengths of colour land at different points along the focal plane

We’ll talk in greater detail about each of these later.

Recognising chromatic aberration.

It can be difficult to tell what has caused imperfections in your photograph. But these are the key indicators of chromatic aberration:

• Outline of colour (red/green/blue/yellow/purple) along the edges of objects
• Colour blurring in the foreground and background of your focal point

Thankfully, there are many ways to counter both types of chromatic aberration – mostly by paying particular attention to certain camera settings, your photographic composition, and shooting conditions.

What causes chromatic aberration?

Chromatic aberration is all about how the camera lens handles light. The lens is one of the most important components in your camera. It draws light to a fixed focal point before sending it onto the camera sensor to make the image.

But this light can be hard to control. This is due to the refractive index (put more simply: the way light passes from one medium to another – i.e. through the glass of a camera lens). Various wavelengths of light travel through the lens at different speeds, making it difficult for some lenses to focus each hue on the same focal plane.

And this failure of a camera lens to focus white light’s different wavelengths onto the same focal point causes chromatic aberration – or to look at it visually, a blur of blue-yellow, red-green or magenta-purple fringing around the edge of objects in your photograph.

What is the cause of chromatic aberration?

One of the main causes of chromatic aberration from a photographer’s point of view is failing to set the right camera settings or to make the right choices about where to shoot. For example, shooting high contrast scenes – such as a skyscraper silhouetted against a blue sky – is likely to create chromatic aberration.

Different types of chromatic aberration.

Let’s now look at the two types of chromatic aberration, so you can easily recognise them next time you see imperfections in your shots. The type of chromatic aberration you’re dealing with depends on what’s happened when your camera lens has tried to process the light.

Longitudinal chromatic aberration.

Also known as: Axial chromatic aberration

What is longitudinal chromatic aberration?

Longitudinal chromatic aberration, or Axial chromatic aberration, often occurs in images made with wide apertures (low f-stop numbers) and where long focal lengths have been used.

What does it look like?

Coloured outlines (blue-yellow / red-green) around the edge of objects in the frame – even in the centre of a frame. For example, window frames on a photo of a house. You won’t solely see it on conventionally shaped objects like skyscrapers and billboards – it’s also present on the edges of irregular shapes, such as branches on trees and craggy mountain tops.

What’s happening in the lens?

Your camera lens has failed to unite the various wavelengths of colour to the same focal plane.

Lateral chromatic aberration.

Also known as: transverse chromatic aberration

What is lateral chromatic aberration?

Lateral chromatic aberration, or transverse chromatic aberration, is the blue-yellow or red-green fringing that occurs when different wavelengths of light focus at varying distances from the lens.

What does it look like?

If the colour distortion is only present towards the edge of the photograph, you’ll know it’s lateral chromatic aberration. Look out for colour fringing with red, cyan, blue and yellow at the edges of your image. If it’s in the centre of the image, it’s longitudinal aberration.

What’s happening in the lens?

Your camera lens has focused the different wavelengths of colour at different positions in the focal plane.

Correcting chromatic aberration.
 

Colour distortion can leave you with photos that look ruined, but thankfully correcting chromatic aberration is relatively easy with the right image editing software and tools.

Digital photography has transformed and democratised post-production editing. In the days of analogue SLR cameras and traditional film, correcting chromatic aberration was a very different challenge to the relatively simple process it is today.

How do I get rid of chromatic aberration?

Removing chromatic aberration is a simple way to improve your image quality and eliminate an unrealistic edge of colour that some beginner photographers may not even notice. You can do it easily with photo-editing software such as Adobe Photoshop and Adobe Photoshop Lightroom.

How do you fix chromatic aberration in Adobe Photoshop Lightroom?