The heart of any digital camera is the image sensor-an amazing device that converts photons, bundles of light energy, into electrons, which are then collected, analyzed, and transformed into a visible image. Unlike all other digital SLRs on the market, the new Sigma SD14 incorporates a 3-layer, 14-megapixel Foveon X3 sensor that is, quite literally, cutting edge. Because this unique sensor captures full color data in all three primary colors at each pixel location, it can resolve finer details in color images than conventional sensors that only capture one color per pixel location. The result: The Sigma SD14 delivers superior real-world performance whenever you shoot high resolution pictures in color-an enormous practical edge you can easily see for yourself in comparison pictures of color test targets as well as in your own colorful digital images.
What makes the SD14's sensor better?
To really understand why the Foveon X3 sensor in the Sigma SD14 is inherently superior to conventional image sensors that use a standard color filter array, let's take a close look at how each type works.
The conventional image sensor
A conventional CCD or CMOS image sensor detects color by means of a specific checkerboard pattern of blue, green, and red color filters added on top of the light-sensitive silicon layer of the sensor chip at the end of the manufacturing process. As a result of this design, there is only one color filter for each pixel location. While the best conventional sensors can take very sharp pictures and provide high color accuracy, their ability to resolve very fine details in color diminishes dramatically as the color details get smaller and smaller. In other words, you may not be able to see some of some very fine color details that are visible in the actual subject reproduced in the final image.
The Foveon X3 image sensor
The Foveon X3 CMOS image sensor, like color film, incorporates three separate light-sensitive layers placed directly above one another-in effect a separate color layer for each primary color. As a result, the Foveon X3 image sensor, unlike the conventional sensor, captures full color data in blue, green, and red at each pixel location. Ultimately, having more and better color information is why the Sigma SD14 can outperform other DSLR cameras in being able to accurately reproduce finer details in color images.