1. What is Chromatic Aberration?
Chromatic aberration or color fringing is a common issue caused by camera’s lens distortion. It is a failure of the lens to focus all the colors to the same convergence point. Less sophisticated lenses and wide angle lenses are more prone to produce color fringing.
Chromatic aberration is visible in photos as a halo or color fringe around objects specifically in a high contrast scenes. If you are photographing against the light or if your subject is positioned on a very contrasty background - the chances are high that you will have to deal with color fringing. The defect tends to increase towards the edges of the frame. The image below is a good example of color fringing - we are looking at detail magnification at 300%:
2. RAW and Chromatic Aberration
The good news is that if you are shooting RAW chromatic aberration can be succesfully corrected in post processing software such as Lightroom or Adobe Camera RAW.
If you had your camera set to JPG - initially the chromatic aberration will be less obtrusive, since it was automatically corrected by the camera. JPG doesn’t offer you any flexibility in further processing, so if color fringing is still visible in your final JPG image - it will be extremely difficult to remove without degradating image quality.
Setting your camera to RAW gives you much more control over the necessary corrections. It allows you great level of precision and a high quality final artwork as a final result. The image below illustrates how chromatic aberration can be quickly fixed with ACR:
3. Fixing Chromatic Aberration in Adobe Camera RAW
Color Fringing can be very quickly corrected in the Lens Correction panel. In the first tab - Profile, select the two options: Remove Chromatic Aberrations and Enable Profile Corrections. The first feature is best kept enabled by default, as ACR deals very efficiently with chromatic aberration.
ACR comes with a set of presets that covers wide selection of lenses - it is always worthwile to check if the lens you were working with is profiled and available in the ACR drop down menu.
The chromatic aberration is the green and purple haze around the edges in contrasting areas. If the automatic option doesn’t fix the issue u may try the manual settings to get rid of the fringing in the image.
Go to the Manual tab and try to be very precise here - narrow the color selection to the range that reflects chromatic aberration in your image. Use large magnification to examine the image.
As you can see, the quality of images can be dramatically improved by correcting the chromatic aberration. Typically all you need to do is to make sure that the Remove Chromatic Aberrations is enabled in the Lens Correction panel. If the automatic correction doesn’t remove the defect from your image - small amount of manual adjustments will help.