A Silicon Valley start-up has come up with a semiconductor that creates a different kind of pixel--one that doubles image quality for something like half the cost. And, oh yes, it lets you make high-quality movies, too. Here's how.
You were just beginning to understand the pixel as something more than just shorthand for "picture element." Perhaps, like me, you were also coming to grips to with its true significance to digital photography. Now this.
Someone has just shown up to change the rules.
THAT SOMEONE is Silicon Valley pioneer Carver Mead. His start-up company, Foveon, has just begun shipping its X3, a new sensor for digital cameras that a source no less august than The New York Times says matches "the quality of film."
Mead, 67, has a long history in the semiconductor and integrated circuit industries and is a professor emeritus at the California Institute of Technology. He started Foveon Inc. in 1997 with the aim of improving the performance of digital cameras--first in high-end professional systems, and now, with the new sensor, in consumer models as well.
The X3 sensor produces approximately 3.53 million pixels. This 3.53-megapixel resolution is no great shakes by conventional standards, where professional cameras generally have 5-megapixels and could really use more.
BUT HERE'S THE THING: Mead's pixels aren't like anybody else's pixels. First, they behave differently. Current technologies require each pixel to capture a specific color--red, green, or blue--which is then assembled and processed to create a more or less lifelike image.
Foveon's chip doesn't pre-assign a color to a pixel; instead, it determines color based on how deeply the photons from the focused image penetrate the X3 sensor. This, according to the company, greatly simplifies capturing the image and improves both resolution and color fidelity. The basic principal at work is that the color of light affects how deeply it penetrates a layer of silicon, allowing depth to be used to determine the color.
The Times quotes a digital imaging expert as saying Foveon may have found "the engineering Holy Grail" of next-generation photography.
THANKS TO ITS new technology, Foveon estimates its pixels are worth about two of anyone else's--meaning its X3 sensors produce resolution equivalent to 7 million regular pixels. We'll get to see for ourselves this spring when Sigma, a Japanese camera company not known as a digital photography leader, is expected to ship the first Foveon-equipped camera, priced at around $3,000.
And, oh yes, Foveon says its sensors are less expensive than the CMOS and CCD sensors used currently. If this is true--and Foveon is able to effectively compete with the big Asian (Sony) and European (STMicroelectronics) companies that provide most of today's sensors--then a price war could be brewing.
This might start as early as this fall if National Semiconductor can turn out Foveon's designs in quantity.
Another claim for the new sensor is that it can easily switch between still and motion photography. This is difficult, because stills require high resolution while movies require a high frame rate (images per second). Foveon is able to combine groups of pixels in such a manner that resolution is lowered while the ability to capture images quickly is enhanced.
In about a year, Foveon expects its manufacturers to introduce a line of consumer cameras that combine an effective 3-megapixel still camera with a digital movie camera. While similar devices already exist, Foveon's will provide equally high quality for both stills and movies.
IT IS PROBABLY worth a mention, for the sake of completeness, that Foveon isn't the only company whose pixels are different. Most people never notice, but one of the reasons for differences between today's cameras claiming the same pixel resolution is that some have slightly larger or smaller pixels. I learned this talking to a Nikon rep, who says his company's best digital camera uses smaller square pixels, while the less expensive models use minutely larger rectangular pixels. In practice this isn't a big deal, but it explains some of the difference in image quality between a semi-pro 5-megapixel camera and a professional model.
Foveon, however, takes this to a new level, and if its quality claims bear out in the marketplace, we may need to find a new way to express image quality in camera specifications. Or perhaps we'll just understand that Foveon pixels are twice as good as the other guy's.
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