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The Sigma – Foveon Story: Revolutionizing Sensor Design?

By Carsten Krieger on March 16th 2014

When I decided to make the digital switch, I was rather reluctant. Digital SLRs were still in their infancy and were just about to become competitive to high quality transparency film like the Fuji Velvia. When I read about the Foveon sensor my heart skipped a beat. Bayer sensors (named after its inventor Bryce Bayer) have been (and still are) the standard, however they can record only one color, red, green or blue, on each pixel site, while the other two colors are interpolated. This means only one color in each pixel is original, the other two are guesswork by the camera’s computer.

Shells, Loop Head

Shells captured with the Sigma SD9

While the Bayer design holds only one layer of sensor sites, the Foveon sensor has 3 layers similar to traditional film. The Foveon design is based on a feature unique to silicon: The different wavelengths of light – red, green and blue – penetrate silicon to different depths so the Foveon designers stacked the sensors for red, green and blue and embedded them in silicon. As a result, the Foveon sensor can record all 3 colors at each sensor site or pixel which in theory should result in more accurate colors and sharper images, because Foveon doesn’t need an anti-aliasing filter.


The first camera featuring this sensor was the Sigma SD9 which was launched in 2002 and it caused quite the confusion. Canon had 6MP DSLR cameras at the market around that time, the Canon D60 and Canon 10D, and was market leader in terms of sensor resolution. Along came Sigma/Foveon and claimed the SD9 which boosted a 9MP sensor (3MP in each layer). The truth, as always, lay somewhere in the middle. The Canon cameras put out larger image files than the Sigma, but were very limited if you wanted to do further enlargement. The Sigma files, however, could easily be enlarged to 400% and more without any significant loss of quality.

River Shannon

These are the situations where the SD9/10 shine: Loads of detail and good lighting conditions

REWIND: An Interesting New Look Inside Sigma’s Aizu, Japan Factory

Unfortunately, the Sigma/Foveon cameras at the time (SD9 and SD10) had one big Achilles heel: Noise and other strange artifacts. Long exposures (over 2 seconds) and high ISO (over 200) were pretty much unusable due to strong noise. There was also a phenomenon that showed artifacts in vast areas of blue skies and became known as ‘blue sky blobs.’ These problems were a result of the basic design of the sensor. Under the right conditions, the Sigma SD9 and Sigma SD10 produced truly outstanding images, but unfortunately the number of these conditions were rather limited. This became a major hindrance for me and I jumped ship when Canon came out with the original Canon EOS 5D in 2005.

Sigma/Foveon kept rather quiet and only announced a successor to the 2003 model, the SD10, in 2006. The Sigma SD14 featured a higher resolution sensor, but showed similar problems to its predecessors. The SD14 was followed by the SD15 in 2010 (although it was already announced in 2008), and also in 2010 Sigma announced the SD1, a flagship camera with a new 4800x3200x3 sensor aimed at the professional market. Unfortunately, this camera made the headlines for all the wrong reasons. It was launched with a hefty price tag (similar to the Canon 1Ds Mark III and Nikon D3X) that only came down after a change at Sigma’s executive level.


The problem: Artifacts and noise in the blue sky despite good light and base ISO

The newest additions to the Sigma – Foveon relationship (Sigma bought the Foveon company in 2008) are the DP compact cameras and their recently announced successors the Sigma Quattro series cameras.

REWIND: Sigma Quattro: New Sensor, New Design… New Camera

The Sigma Quattro cameras feature a completely new sensor design that should eliminate the noise problem of the older Foveon design. If the theory works out, Sigma/Foveon could be on the way of revolutionizing sensor design. A sensor that captures full color information in each pixel, but also displays low noise at long exposures and high ISO is something many photographers would be happy about. Imagine a sensor like that paired with Sigma’s new series of lenses. That would be a game changer. I definitely will be watching Sigma more closely again.

What are your thoughts on the new Sigma Quattro and the changes they’ve made?

CREDITS: All photographs by Carsten Krieger are copyrighted and have been used with permission for SLR Lounge. Do not copy, modify or re-post this article or images without express permission from SLR Lounge and the artist.


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Carsten Krieger is a freelance photographer based in Ireland. He is covering a wide range of subjects including architecture/interior, portrait and food (and with a proper supply of of tea and chocolate he is able to shoot about anything), but his true love is landscape photography. He has published and contributed to a number of books on Ireland’s landscape, nature and heritage and has written for various print and online magazines.

Q&A Discussions

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  1. Paul Monaghan

    I just got a dp3m and used in the right situations the IQ is simply outstanding, so much so that the first test shots I did made me think that my dslr was broke or miss focused but re doing the test with different lens showed the same results.

    Also looking online showed similar results with the sigma dp merrills even out resolving d800e exspecially in whites (think clouds and other fine white textures).

    sure the camera is slow, the af sucks, lcd refresh in low light is pretty bad, around 60 shots per battery, anything over iso 200 and your as well as using ur dslr but the iq is worth it.

    I’m not sure if the new versions will be as good as they are doing away with full colour per pixle and going from 3×15.6 to 20×4.6×4.6 (or there about) and the new cameras are much bigger so it could be an idea to grab the merrills while you can and at £340 each in the uk for a camera that needs mf to best it in iq it would be silly not to grab atleast one before they are gone.

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