PetaPixel

Scratching the Color Filter Array Layer Off a DSLR Sensor for Sharper B&W Photos

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In October 2012, astrophotographer Raymond Collecutt of Whangarei, New Zealand shared a new (and risky) idea he was playing around with: converting a standard DSLR into a sharper monochrome camera for photographing space.

After removing the glass layer that’s covering the sensor of his Canon 1000D (“It pops off slowly with a small screwdriver,” he says), Collecutt started scratching the green layer from the surface of his sensor using a soft point. This layer is the color filter array (CFA) that helps capture color information. It’s a layer that’s directly on the surface of the sensor (unlike the infrared filter, which sits above the sensor).

Here’s a video showing the layers being scraped off:

Collecutt’s initial tests were rough but promising. He didn’t remove the color filter layer to the edges of the frame, since there were important little wires at the sides. “I’m going to have a better go at cleaning the sensor up,” the photographer wrote at the time:

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Despite the rough removal job, resulting photographs captured using the modified sensor showed more sensitivity in the monochrome areas:

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His first tests with photographing the night sky were also promising:

The same scene photographed with a standard DSLR (left), and a DIY monochrome DSLR (right)

The same scene photographed with a standard DSLR (left), and a DIY monochrome DSLR (right)

Regarding the advantages of this dangerous hack, Collecutt offers a sunglass analogy, saying, “It’s like taking its sunglasses off. If you were to put [a filter] in front of a standard DSLR, only one out of four pixels would be getting the light, but with the bayer filter removed all four pixels will be getting the same amount of light.”

In the months that have passed since Collecutt’s initial tests, other photographers have continued tinkering with their own sensors and building upon Collecutt’s idea. The original forum post is now 25 pages long.

A photographer named Dave reported that scratching off the layer removes both the color filter layer and the microlens layer above it. Losing the microlenses reduces sensitivity, but removing the filter increases it. He says the optical improvement isn’t very big, but there are big gains to be had in IR and UV photography.

Dave also discovered that he could easily scrape off the filter layers using a scraping tool made from the plastic end of a paintbrush. This removes the filters without damaging the sensor underneath.

February of this year is when photographer Luis Campos got in on the action. He discovered that he could remove the CFA layer by cracking the layer open with a small hypodermic needle, and then scraping off the whole thing slowly using a carved wooden tip:

Campos writes that this DIY monochrome DSLR is “a great tool for the low budget amateur astronomer,” and that the removal of the CFA more than makes up for the loss of the microlenses. He has been posting some beautiful astronomy photographs taken with his “Mono Canon” to his Flickr account. You can find two of them here and here.

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If you’d rather not put your camera at risk with this crazy DIY hack, you can shell out some serious cash for a Leica M Monochrom, the new commercial camera that comes without the color filter array.

Want a more in-depth look at how this hack is done and how it was developed? You can read through the 25 pages of “research” done so far by the members of the Stargazers Lounge forum. It’s interesting seeing how things have progressed from Collecutt’s initial discovery to Campos’ completed hack.

(via Stargazers Lounge via Reddit)


Image credits: Photographs by Raymond Collecutt and used with permission