PetaPixel

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

sensor

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:

scratched

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

sensitive

sensitive2

dogtest

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.

9405302732_462301ddc5_c9402541477_771c30d5fc_c

 

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


 
  • steve stevenson

    It would be fun to try this out with some older DSLRs that you can get for $100.

  • http://www.facebook.com/nanonyous Theo Lubbe

    What I’d like to see is side-by-side comparisons of two shots taken with the same relative exposure, one with model x of a camera on which the sensor’s filter has been removed and the other on the same model camera without it removed, then converted to BnW.

  • incendiary

    scrape off half the layer and leave the other half?

  • http://www.facebook.com/nanonyous Theo Lubbe

    Hah – I’d prefer being able to compare the two shots by flicking between them. I’m interested in how this affects dynamic range, as it appears from the worktable shot as though it may actually improve things slightly.

    I’d personally consider this for uses that don’t include astrophotography. I wonder what kind of results could be yielded from a 1DX or D3s *cough*

  • John

    Canon 5d Mk M (Monochrome) :D

  • http://www.jbphotographic.co.uk/ Jamie Barlow

    I have a D60 with a scratched sensor (messed up a cleaning job) that would be perfect to try this on… Do you think it would work? I don’t actually know what part of the sensor is damaged but is better than of collecting dust on a shelf.

  • http://bit.ly/mattaka Matthew Wagg

    That is some scary stuff. More power to the people that do these conversions.
    I wonder if they replace the highpass filter with another piece of glass to retain AF and TTL?

  • jrconner

    You need the nerves of a cat burglar to try this. And pockets as deep as a Wall Street banker’s.

  • Andrew Iverson

    Seeing the bit about it being useful for IR makes me wish Lifepixel would do this. I’m interested in trying this, but not quite brave enough. ;)

  • Mike

    Nah, you can get used low end DSLRs for real cheap these days.

  • mark

    this a great idea, the speed camera are changing I already have two spares that are only 8 and 12 meg , I think I should be sober though .

  • jrconner

    Spoken like a Wall Street banker.

  • AluKed

    If it’s scratched by a botched cleaning job, you most probably scratched the IR mirror/OLPF that actually sits above the sensor itself. If that’s the case, you can surely do this to the camera (or you can just do a quick search online, get a neutral glass plate and substitute for the IR/OLPF and get a neat color+IR camera).

  • SaveTheWorldGetTheGirl

    Eh, you can get a used Nikon D80 for $120 … that’s hardly going to break the bank if you really wanted to try something like this.

  • Jonathan Maniago

    Doesn’t the processing of the image file still go through the demosaicing algorithm associated with that camera model?

  • Rabi Abonour

    Fortunately, if he’s just using the cam for astrophotography, I doubt he cars about either AF or TTL.

  • Mike

    What is wrong with you, man?
    One can buy a DSLR for his photographic needs, but modifying a cheap low end model is consistent with your obsession with Wall Street bankers?

  • kassim

    Good one incendiary!!! Hahahahah…

  • kassim

    Yeah, I wonder about that too.

  • Mike

    Well, with a Bayer pattern every R/G/B pixel gets a different amount of light.
    But here, because all RGB locations got an unfiltered exposure, one should be able to see a correct image without demosaicing.

    I have no idea how a demosaic algorithm would react to such a situation, but maybe if it sees similar values in all RGB pixels, then it spits out a greyscale image?

  • Mike

    I mean, wouldn’t it be the same as using a Bayer pattern to photograph a black and white printed target?

  • Dan

    It was a joke

  • AT-AT

    If you don’t want to pay for Leica M Monochrome, why don’t you try a Sigma’s Foveon sensor-equipped camera (SD1 Merrill or DP1/2/3 Merrill), or even older models (SD15 or DP1/2)?

  • http://www.eriklaurikulo.se/ Erik Lauri Kulo

    “the new commercial camera that comes without the color filter array.”

    I’m sorry to nitpick. But please place the italic on the right word. Why would you emphasize the word “comes” instead of “without” in this case?

  • Petchalxande

    Balls of steel.

  • http://alphacorner.eu/ Sky

    Uh? They got CFA too.
    And a horrible high-ISO making them even more useless for astrophotography than regular DSLRs, even before scratching the CFA off.

  • Zos Xavius

    In a classic DSLR the PDAF sensors and meter cells are part of the mirror box and pentaprism respectively. You could replace the sensor with a piece of tin and they should still operate just fine.

  • bkf11

    There is a glass cover over the sensor – that will be what is scratched. As AluKed says, you could replace that cover or as done in the article, remove the cover and have a go at scratching the colour filter array off and make a monochrome D60. If that’s all that is wrong with the camera, it would be a perfect candidate for this hack.

  • bkf11

    If not, you can use LiveView to focus.

  • bkf11

    I think that you can get the raw image file (before demosaicing) using an option in the ‘dcraw’ software.

  • NancyP

    Foveon sensors do NOT have a CFA. The color discrimination is achieved by measuring photon depth penetration within silicon. Every pixel has an R, G, and B readout. Yes, the color is dreadful at high ISO, but many people have used the “blue” channel for good quality at ISO 1600 and 3200.

  • Danny Garside

    Surely you’d also need to find a way to access un-de-mosaiced data from the sensor for it to be of any advantage whatsover?

  • Jakub

    Will my camera be more sensitive for light (for example from 1/100 to 1/300) after removing color filter?

  • Harlock

    It’s not really a new discovery, i first read about people removing the bayer filter at least 6 years ago when i was researching about doing it myself,