Chromatic aberration is just a fact of life when it comes to photography. A combination of high-quality gear — lenses in particular — and user skill can minimise the tell-tale purple fringe. But what if a simple layer on your lens could all but eliminate CA? Enter a team of researchers from Harvard's School of Engineering and Applied Sciences (SEAS), who have accomplished exactly this.
Called a "metacorrector", the coating is composed of a "single-layer surface of nanostructures", according to a press release from SEAS.
The structures can be seen in the image below.
The structures, or "nanopillars", alter the speed at which light reaches the focal point, reducing or eliminating chromatic aberration:
“You can imagine light as different packets being delivered at different speeds as it propagates in the nanopillars. We have designed the nanopillars so that all these packets arrive at the focal spot at the same time and with the same temporal width,” said Wei Ting Chen, a Research Associate in Applied Physics at SEAS and first author of the paper.
Here's another image, showing photos taken without (left) and with (right) the metacorrector. As you can see, the difference is substantial.
I know we're all here drooling over the prospects for photographers, but the technology has many applications — for example, on high-resolution microscopes where clarity is paramount.
And, while Harvard is "exploring [commercialisation] opportunities", I think it'll be some time before it filters down to us plebs.
Chromatic aberration is the unwanted distortion of colours that you sometimes notice on the edges of your photos. It happens because colours of light have different wavelengths, which means your camera lens refracts them slightly differently. Here's a quick fix to compensate in Photoshop.