How to deal with chromatic aberration ?
One of the most common mistakes landscape photographers make, is forgetting ( somewhere in the editing process ) to deal with chromatic aberration, also called color or purple fringing. It’s a common optical problem that occurs when a lens is either unable to bring all wavelengths of color to the same focal plane, and/or when wavelengths of color are focused at different positions in the focal plane.
Pfeww, that sounded techy no ?
Now, I’m not going to dive into the technical specifics, wikipedia is way better in that then I am !
But basically it boils down to the fact that it occurs in transition aria’s between really bright and dark aria’s. Edges of objects in your picture show a red, blue or green color fringe, but at least in my experience it most often appears as a purple fringe.
But I’ll briefly show by means of example images what it is, and how to deal with it. I’m also going to show you a way how to bring CA correction into your editing workflow and how to remove it from your images.
There is one thing that is of most importance and that is that you shoot in RAW ! This will give you full option on controlling your data in preparation before the actual editing. Either with HDR workflow or not. If you don’t remove chromatic aberration from the RAW data even when you practice an HDR workflow, the problem will get worse / more visible in the editing process !
Before you even start thinking about editing your images, it is best practice to first start with getting rid of CA !
So, if you open up photoshop bridge and your images are imported, double click on the raw data image and it’ll open in Camera Raw that is included in the photoshop package.
Camera Raw, a RAW converter is openend. It is also possible to do RAW converting in Lightroom or a more advanced software called Capture One. But that’s for another post…
Next you want to click on the lens correction filter. Camera RAW will automatically recognize the lens you’ve used ( at least the most common ones ) and will deal very effectively with any lens-related problems.
Next you click on the “Color” button map, and also click on the “remove chromatic aberration” square. Camera RAW will do mostly a very good job in removing the color fringing.
Here you can see a before
And after correction
Ones the chromatic aberration is corrected click save image, and camera raw raw will develop your tweaked RAW data into a TIFF file.
Best is to go for a 16bit with an sRGB color profile. If you use a HDR app, it are THESE files to use to import into it in order to create the final HDR picture.
It can happen sometimes that the chromatic aberration correction doesn’t do a proper job. You can then by hand and eye deal with the correction with the “defringe sliders”, but that would make this post too long. I will handle that later in a “how to” vid tutorial.
Hopefully you’ll be good on your way with this very important correction, that so often is overlooked and not understood.
In case you have any question, feel free to drop a line and shoot !
Happy to help, if I can !