Digital Camera Designed to Rival Film

Camera maker Sigma is preparing its first move into the digital still camera market with a model using X3 image sensor technology from Foveon, Sigma announced Tuesday. The technology allows for more accurate and rich color reproduction of digital still images, the two companies said.

Sigma will unveil a prototype of its SD9, a single-lens-reflex and lens-changeable digital still camera on February 24 at PMA 2002, the Photo Marketing Association show in Orlando, Florida, according to a Sigma statement.

The SD9 will be the first digital still camera to use Foveon's X3 image sensor technology, which the company only announced on Monday.

Existing image sensor technologies use either a CCD or a CMOS chip, which consists of one layer of light-sensitive pixels. These cannot distinguish different wavelengths or colors of light, and so just record monochrome images. In order to capture colors, a filter made up of a mosaic of the three primary colors (red, green, and blue), is placed over the chip's pixels. However, each pixel captures just one color, red, green, or blue.

Foveon took advantage of the fact that silicon absorbs light of different colors at different depths, and built its X3 image sensor with three superimposed layers of light sensitive pixels, one each for red, green, and blue, so each pixel can capture all three colors, the statement says. Allowing each pixel to capture the three colors results an image becoming sharper and much closer to film image quality, without increasing the number of pixels, according to Foveon. Using only one chip is much cheaper than multi-chip systems using three CCDs, it says.

Similar to Film

"The theory of the X3 technology is similar to the theory of color films, that is why the final images captured by the SD9 get closer to film image quality," says Teruaki Kuwayama, a spokesperson at Sigma. The company is targeting users of its film cameras with an interest in digital still cameras, he says.

The Sigma SD9 has a 3.5-megapixel image sensor, and can produce images at a maximum resolution of 2,268 by 1,512 pixels. It also has IEEE1394 and Universal Serial Bus interfaces, and a video output which can switch between NTSC and PAL signals, two different video formats used in different countries. The camera stores images on Compact Flash cards, Sigma's statement says.

The camera measures 5.9 by 4.7 by 3.1 inches, and weights 1.8 pounds without batteries. At the back of the camera, a 1.8-inch thin film transistor color LCD viewer is attached. Some of Sigma's film camera lenses can be used with the SD9, Kuwayama says.

Because the product is still a prototype, the company has not yet planned a launch date or set a price, Kuwayama says.