Chromatic aberration: what is it and how to remove it | Articles | Photo, video, optics

How to make a pho­to pleas­ing to the eye? Ensure that it is not over­ex­posed or too dark. Raise con­trast and sharp­ness. And, of course, remove the flaws that optics intro­duce. These include dis­tor­tion of the image due to the type of lens (for exam­ple, a wide-angle lens stretch­es the cor­ners), vignette and chro­mat­ic aber­ra­tion.

We under­stand what chro­mat­ic aber­ra­tion is, how to remove it in dif­fer­ent graph­ic edi­tors — Pho­to­shop, Light­room and Cap­ture One.

Pho­to: Eliz­a­beth Chechevic / instagram.com/chechevic_a

What is chro­mat­ic aber­ra­tion
Cause of chro­mat­ic aber­ra­tion
How to avoid chro­mat­ic aber­ra­tion
How to remove chro­mat­ic aber­ra­tion
How to Remove Chro­mat­ic Aber­ra­tion in Pho­to­shop
How to Remove Chro­mat­ic Aber­ra­tion in Adobe Cam­era Raw
How to Remove Chro­mat­ic Aber­ra­tion in Light­room
How to remove chro­mat­ic aber­ra­tion in Cap­ture One

What is chromatic aberration

Chro­mat­ic aber­ra­tion is the dis­tor­tion that occurs when light pass­es through an objec­tive lens. Usu­al­ly these are col­ored halos or stripes that were not in the pho­tographed scene.

Most often, chro­mat­ic aber­ra­tions appear at the junc­tion of con­trast­ing bound­aries. These are places where two dif­fer­ent col­ors or bright­ness­es col­lide. For exam­ple, a mod­el in a black coat against a bright win­ter sky.

Cause of chromatic aberration

Chro­mat­ic aber­ra­tion occurs when a light beam is refract­ed into a spec­trum. That is, light enters the lens and is refract­ed there with the help of lens­es.

We can see the refrac­tion of light in the form of chro­mat­ic aber­ra­tion in pho­tog­ra­phy due to par­a­sitic dis­per­sion, when the focal lengths for rays of dif­fer­ent col­ors do not match. This hap­pens because col­ors have dif­fer­ent wave­lengths. It is because of this that chro­mat­ic aber­ra­tion can be red, pur­ple, yel­low, and any oth­er shade.

We are talk­ing about the dis­per­sion of light, which New­ton dis­cov­ered back in 1672. One of the sim­plest and most under­stand­able phe­nom­e­na of dis­per­sion is the rain­bow or flash­es of light that play in cut gem­stones.

Illus­tra­tion of New­ton’s expe­ri­ence. A beam pass­ing through a prism is decom­posed into a spec­trum of pri­ma­ry col­ors. Chro­mat­ic aber­ra­tion is when we see one of these col­ors dur­ing refrac­tion / wikipedia.org

How to avoid chromatic aberration

• First of all, the appear­ance of chro­mat­ic aber­ra­tions is influ­enced by the prop­er­ties of optics. There­fore, use high qual­i­ty pro­fes­sion­al series lens­es.

Or read detailed reviews before buy­ing — a good review will always con­tain infor­ma­tion about lens chro­mat­ic aber­ra­tions and oth­er opti­cal dis­tor­tions.

• Shoot at high­er aper­tures. For exam­ple, around f4-f5.6. This is espe­cial­ly true for ama­teur-lev­el optics.

Com­pen­sate for the lack of light by rais­ing the ISO, short­en­ing the shut­ter speed, using exter­nal flash­es. Here we tell you how to set up a cam­era flash.

• If you have a zoom lens, shoot at medi­um set­tings. So, if the lens is 24–70mm, then at 24mm the chance of get­ting chro­mat­ic aber­ra­tion is high­er than when shoot­ing at 40mm.

If none of the meth­ods helped and chro­mat­ic aber­ra­tion still appeared, then it can be quick­ly removed in post-pro­cess­ing. Below we will tell you how to do this in dif­fer­ent graph­ic edi­tors.

How to remove chromatic aberration

Chro­mat­ic aber­ra­tion is a col­ored halo or line around an object. It turns out that in order to remove this opti­cal dis­tor­tion, you need to find it and dis­col­or it. The removal of chro­mat­ic aber­ra­tions in any graph­ic edi­tors is based on this prin­ci­ple.

In the illus­tra­tion on the left, pur­ple chro­mat­ic aber­ra­tions on the build­ing are vis­i­ble at close prox­im­i­ty. In the pho­to on the left, chro­mat­ic aber­ra­tion was removed using Pho­to­shop / Illus­tra­tion by the author

How to Remove Chromatic Aberration in Photoshop

This option is best for those who shoot in .JPEG.

1. Open a pho­to.
2. Dupli­cate the lay­er. To do this, in the palette Lay­ers click on the lay­er with the right mouse but­ton on the lay­er and select Dupli­cate lay­er / Dupli­cate Lay­er.

You can quick­ly dupli­cate a lay­er using the Ctrl+J hotkey / Illus­tra­tion by the author

3. Select the dupli­cate you just made. Go to Fil­ter / Fil­ter — Blur / Blur — Gauss­ian Blur / Gauss­ian Blur. The blur radius depends on the size of the pho­to and is select­ed exper­i­men­tal­ly. But you can focus on val­ues ​​​​from 2 to 7 pix­els.
4. Apply blur. After that put the blurred lay­er in blend mode Col­or. Do not con­fuse with Chroma/Hue.

How to Remove Chromatic Aberration in Adobe Camera Raw

An option for those who shoot in .RAW. The first thing you’ll see when you open Pho­to­shop is the Adobe Cam­era Raw (ACR) mod­ule for devel­op­ing RAW files.

1. Open the file in ACR and find the tab Lens Cor­rec­tions / Lens Cor­rec­tions.
2. Check the box Remove Chro­mat­ic Aber­ra­tion / Remove Chro­mat­ic Aber­ra­tion.

An exam­ple of chro­mat­ic aber­ra­tion. On the left is the image before it was removed. It man­i­fest­ed itself in the form of blue and red halos along the con­tour of the tree / Illus­tra­tion by the author

How to Remove Chromatic Aberration in Lightroom

1. Import the desired file into Light­room.
2. Go to the tab Devel­op.
3. On the left side of the screen at the bot­tom, find the tab Lens Cor­rec­tions / Lens Cor­rec­tions.
4. Click the check­mark Remove Chro­mat­ic Aber­ra­tion / Remove Chro­mat­ic Aber­ra­tion.

An exam­ple of chro­mat­ic aber­ra­tion. On the orig­i­nal, it appeared as pur­ple and blue halos around the branch / Illus­tra­tion by the author

How to remove chromatic aberration in Capture One

Cap­ture One removes chro­mat­ic aber­ra­tions by default as soon as you open a RAW file in it. But, if for some rea­son the func­tion did not work, then the algo­rithm is as fol­lows:

1. Find the but­ton Lens Cor­rec­tions in the form of a cir­cle.

Depend­ing on the set­tings you have spec­i­fied, the main edit­ing pan­els can be on the left or right. In this case, they are on the left by default / Illus­tra­tion by the author

2. Click the check­mark Chro­mat­ic Aber­ra­tion / Cro­mat­ic Aber­ra­tion. Then the pro­gram will auto­mat­i­cal­ly find dis­tor­tions in the image and dis­col­or them.

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