Authored by Michael Anissimov and can also be found here:
Digital Camera
Instead of exposing a photosensitive chemical known as film to a scene to create an imprinted image, most digital cameras use a charge-coupled device (CCD), an electronics instrument that creates a pixel map based on the electric charge generated when photons slam into a sensitive material. This phenomenon is called the photoelectric effect, and was elucidated by Albert Einstein in a famous 1905 paper. Less frequently used than a CCD is a complementary-metal-oxide-semiconductor (CMOS). Because it is the digital camera mechanism in the minority, the CMOS will not be discussed in this article.

The term CCD-based camera is sometimes used interchangeably with digital camera, because by its very nature the CCD-based camera takes digital camera pictures – pictures with a certain pixel-by-pixel resolution that can be encoded digitally. Nowadays, we can transfer these files from a digital camera to many devices, including computers, screens, phones, and printers.

A charge-coupled device is an integrated circuit, meaning it uses multiple semiconductor elements on a unified platform to achieve its goals. The active components of the charge-coupled device in a digital camera or other CCD-based camera are the capacitors. These are linked in a circuit, hence the term charge-coupled. A capacitor is a basic electronics device that stores a potential difference, or voltage, in the variance between two plates with equal but opposite electrical charges.

Digital Camera
A lens projects the image onto the CCDs. Each capacitor acquires a charge proportional to the brightness of incoming light. CCDs are not inherently color-sensitive, and to take color photos, a Bayer mask must be employed to selectively filter light into designated pixels based on color. Upon acquiring the charge, the capacitors begin passing their charge to adjacent capacitors in a charge-coupled, daisy-chain fashion. A register at the end of a capacitor array makes the appropriate measurements, and a 2D pixel map is created.

Because their sensitivity to light is about 35 times that of a conventional camera, approaching the quantum limit, the digital camera is favored by event photographers and astrophotographers alike. Because of the lack of active chemical components, images on a digitalcamera do not need to be “developed” and are stored directly in the camera shortly after exposure.

For all your Digital Camera needs, check out our digital cameras page under gadgets.

Leave a Reply.