Understanding Image Sensors

Sophisticated technology goes into the design and manufacture of your digital camera. Understanding some of that technology can help you to predict how the camera will fare when you’re shooting in a variety of situations. For our annual How-To issue, we’re including this article on the anatomy of an image sensor. The overall image quality in your photographs is dependent upon a number of factors in addition to sensor resolution. Lens quality, in-camera processing, compression algorithms and just plain old shooting technique all work together. Still, the image sensor is the core around which the rest of the camera is built.      
             
Much more than a simple replacement of film, the sensor is a high-tech piece of electronic wizardry. There are two types of image sensors used in today’s digital cameras: charge-coupled devices (CCDs) and CMOS chips, which is an acronym for complementary metal-oxide semiconductor. The names don’t help to explain what they do. CCD refers to the design of the chip, and CMOS refers to the chip’s manufacturing process. While the vast majority of image sensors are CCDs, both of the devices are designed to achieve the same result: converting light into an electrical charge. And although both devices are made of silicon, it’s how they operate that differentiates them.