Color Fringe

Main Street Diner

The difference between good and great is often in the details.

In the past, I’ve talked about the importance of a tripod for landscape images.  It may be a small thing, but it makes a measureable difference in the clarity of the image.  Crisp edges can be the difference between good and great.

Along those same lines (see what I did there? Lines? Edges? Waka waka!), one of the things that can make an image appear less than sharp is chromatic aberration.  This distortion is a failure of the lens to focus all of the colors to the same convergence point.  This manifests itself as a color fringe where light and dark parts of an image come together, especially in the outer quadrants of an image.  In other words, items within the frame will appear to have cyan, yellow, red or blue glowing edges.  The degree of aberration generally goes hand in hand with the quality of your glass.

Now, obviously, not everyone can afford high end glass, but most people can compensate for these color defects in their editing software.  I won’t pretend to be familiar with all image editing software, but I can tell you with certainty that Lightroom gives you the ability to reduce the appearance of the aberration, which will subsequently increase the appearance of sharpness.

That by itself is impressive.  It’s an instant way to increase the quality of your images.  However, if you intend to process your image for HDR it becomes imperative. (Phew!  That’s a lot of alliteration.)  The reason chromatic aberration becomes so important in HDR processing is because you are merging three or more exposures, which means you are compounding the problem times 3 (or more).

Checking for CA is a simple habit to get into.  Although severe CA is noticeable with the naked eye, often I will zoom in to get a good look at the edges of subject matter within the frame.

CA Example

Some images need no corrections, in which case I move on to the next step in my workflow.  For the ones that show distortion, personally, I simply adjust the sliders in LR while the image is still in RAW format, before I export it for finishing touches elsewhere.  BAM! Done.

CA Example 2