[Voice of Jerry Seinfeld saying "Newman!"]: Sigma!
Sigma, one of the major independent lensmakers, is also one of the most quixotic, frustrating, and yet interesting cameramakers on the planet. It was the original licenser of the Foveon sensor invented by Carver Mead, an early pioneer of microelectronics and the man who coined the term "Moore's Law," in the year 2000, and it bought Foveon Inc. lock, stock and barrel in 2008.
Although Sigma cameras with the Foveon X3 sensor have had modest success, when I think of Foveon I can't help but think of the innovative cone loudspeaker driver of Lincoln Walsh (1903–1971). The Walsh driver has some real advantages over conventional loudspeaker drivers, but the technology has been locked away in the hands of a tiny speaker manufacturer called Ohm for lo these many years. The intent was to capitalize on the design; the effect has been to marginalize it. Ohm is not a bad company—a small band of dedicated guys toiling away in Brooklyn—but there's no sense pretending it's ever going to take the world by storm. Meanwhile, mainstream speaker design and manufacture has gone around the Walsh driver like water in a river going around a rock.
I can't help but think that if Foveon technology were available freely to all cameramakers, the Bayer array sensor would be a quaint remnant of digital photography's history by now. Consider a parallel Universe where all the intensive R&D by Sony, Canon, Kodak and Fuji had gone into Foveon-type 3-layer sensors—it boggles the mind as much as science fiction. Instead, Foveon technology is the property of Sigma, a large lensmaker and small cameramaker. Sigma has done a decent job of marketing it—but let's not pretend it's taken the world by storm. For eight years now, Sigma has ambled along making a small number of adequate cameras with this interesting sensor in them...cameras that are typically not on time to market and a half skip to a skip-and-a-half behind the moment, and undeniably outside of the main current of digital imaging technology. Sigma has always insisted in giving the resolution figure of its rather modest 13.8 x 20.7mm*, 2640 x 1760-pixel** basic sensor a "times three" value, which, while sort of correct, works against its own interests, because in fact it doesn't match the resolution of a 14-MP Bayer array (for whatever reason), and it's generally seen as a marketing exaggeration by the camera-buying public. Meanwhile, you get the sense that if Panasonic or Samsung got their mitts on this technology, they would use it annhiliate the rest of the camera market and stand astride our world like a conquering colossus. In Sigma's hands, by contrast, it's sort of like the weird kid in class off doing something strange in the corner.
And yet. There is something undeniably very special about the Foveon X3 sensor. Purely aesthetically, Foveon pictures have a quality that can often be easily seen. I once likened the Foveon's relationship to the Bayer array as being like that of Kodachrome to a tri-color camera (a tri-color camera was a complicated, klunky Rube-Goldberg device that essentially used beam splitters to record the red, green, and blue components of a color image on three pieces of black-and-white film simultaneously). The Bayer array is essentially inelegant, the Foveon sensor essentially elegant. A Bayer array essentially recreates a color image, from a patchwork of information that has to be interpolated; a Foveon sensor records it directly. The Foveon sensor doesn't suffer as much from moiré effects, so it doesn't need a sharpness-destroying anti-aliasing filter. Sigma says it is sharper and purer "pixel for pixel" than any Bayer-array sensor. True...except, what do you mean by "pixel"? It certainly is better if you compare it to a conventional 4.6-MP sensor. The advantages aren't quite as clear if you use the times-three numbers and put it up against everything the biggies have been able to accomplish with the Bayer array.
Big day...sort of
In any event, Sigma has just announced, at Photokina, an all-new flagship camera called the SD1. Although that's big news, it's not the big news. The big news is that after using versions of similar-spec'd Foveon sensors approximately since digital crawled out of the emulsified swamp with four legs and a tail, Sigma has debuted a much larger Foveon sensor. The new sensor is 24×16mm in size, or true APS-C, and it has 4,800×3,200 photosite locations. That would be 15.4 megapixels if measured only by the standards of conventional Bayer arrays, which of course isn't accurate or fair, and it's a whopping 46 megapixels by Sigma/Foveon's habitual X3 computation—which is also probably not exactly accurate, subjectively speaking and all.
And yet. Ctein's back-of-the-napkin calculation is that the SD1 sensor will grab the mantle from the Sony A900 as the highest resolution sensor in a conventional DSLR body.
And image quality? That of course remains to be seen. And therein lies a whole 'nuther tale. Sigma has a well-deserved reputation for lagging behind its promises when it comes to product introductions, sometimes very significantly. (Remember how the weird kid never turned anything in on time, but when he eventually did, half the time it was brilliant?) The SD1 is slated to ship in February, and I'm tempted to say that if it does I'll eat it. But Sigma the cameramaker and especially the Foveon sensor maker is a cut-'em-some-slack case in the camera firmament if there ever was one. In the parallel Universe of What Might Have Been, this would have been by far the most significant announcement not only of Photokina, but of 2010. Even in this world, it more than bears watching. More news as the months tweedle by.
* That's in between APS-C and 4/3rds size.
** That would be considered a 4.6-MP sensor if it were a Bayer array. These figures are from the SD14, by the way.
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Original contents copyright 2010 by Michael C. Johnston and/or the bylined author. All Rights Reserved.