Chromatic aberration, also known as "colour fringing" or "purple fringing," is a common optical problem that occurs when a lens is unable to bring all wavelengths of colour to the same focal plane. This results in a failure to converge all colours to the same point, leading to a mismatch of colours around the edges of objects in an image.
There are two main types of chromatic aberration:
Longitudinal (axial) chromatic aberration: This occurs when different wavelengths of light are focused at different distances from the lens. It can result in coloured halos around objects that are out of focus.
Lateral (transverse) chromatic aberration: This occurs when different wavelengths of light are focused at different positions in the focal plane. It typically appears as colour fringing around the edges of objects, particularly towards the edges of the image frame.
Chromatic aberration is more pronounced in high-contrast situations. This is where I usually run into it, especially when I'm photographing in the 'high key' style - and I love this look - so 'Chrome Ab' and I are almost friends 😂
If you'd like to receive to my monthly newsletter with news and notification of new posts, I invite you to subscribe....no sharing your deets and I promise I won't spam you too often! Easy to un-sub with a click if you're over it...
Here's an example of Chromatic Aberration - I was shooting directly into the sun. My darling Cockatoo subject's eyes and faces were in shadow. I overexposed to bring out the expressions, knowing full well I was blowing out the sky...
See the distorted halo effect around some of the leaves, especially at the outer edges of the frame? That's Chromatic Aberration:
Technically, it's a pretty bad shot, but the birdy behaviour was so endearing I wanted to persevere and see if I could make it into something, albeit with a solid dose of post processing....
So here's the end result, edited in Adobe Lightroom. The heavily 'Chrome Abbed' leaves and a few extra bits and branches removed using the 'Inpainting Brush Tool' in Affinity Photo. I then cropped whole image to further reduce distractions. About 3 minutes editing.
Far from my best shot ... but it's passable for social media ... and they are very cute, which makes up for a lot!
Chromatic Aberration can minimised or corrected through various methods, including:
Using achromatic or apochromatic (APO) lenses* (see below) that are designed to bring two or more wavelengths into focus in the same plane.
Correction in post-processing software.
Stopping down the aperture (raising the numerical value, therefore decreasing the size of the lens opening), although it may not completely eliminate it. Just switching from say f4 to f9 or so - if you have the light and the time to do so - can make a difference.
Higher quality lenses.
*In short (I may elaborate on this in a future blog post)
Achromatic lenses correct two colours and are more affordable.
Apochromatic (APO) lenses correct three colours and offer superior quality - of course at a higher cost - but when it comes to lenses, you usually get what you pay for. A better quality APO lens, which usually contains 3 pieces of glass rather than the 2 of Achromatic lenses, will help to minimise you running into 'Chrome Ab' on a regular basis.
Here's another example - this image has multiple issues: chromatic aberration, white balance is off (too cool) and wrong placement of the subject. This Scaley-breasted Lorikeet is smack bang in the middle of the photo, defying the rule of thirds. But as he is sharp, the image is not unsalvageable, with some post processing adjustments.
With white balance correction, cropping and selective editing on the background using masking to blow the background up even more, I've removed much of the chromatic aberration and brighten the image, which was taken in deep shade.
I then removed more of the damaged areas using an object remover tool - Affinity Photo's Inpainting Brush Tool - to take away even more of the affected areas. There's a similar removal tool in most post processing software than can do away with a few unwanted distractions. A little bit of Clone Stamp helped to even out the background further.
Here's our little Lori again, looking almost acceptable. Not a high quality shot and certainly no competition entry, but good enough for my holiday photo album and social media! I don't mind the blurred leaves, they are soft enough not to detract from our main subject.
Chromatic Aberration usually appears when you have less-than-perfect light conditions and therefore a less-than-perfect image. But it is possible to minimise it and salvage your photo using post processing.
It's not something you need to fret over, but knowing what Chromatic Aberration is, why it appears and how to fix it, is a useful skill. You're bound to run into it somewhere along your photographic journey!
Comments