by Bob Brooke

On October 17, 1969, George Smith and Willard Boyle invented the charge-coupled device (CCD), the image sensor that’s the heart of all digital cameras, at Bell Labs. But like many inventions originally designed for one use, Smith and Boyle were attempting to create a new kind of semiconductor memory for computers. At the same time they were looking for a way to develop a solid-state camera for use in video phones. It took just an hour for them to sketch out the CCD’s basic structure, define the concept of its operation, and outline the applications for which it would be best suited.

By 1970, Smith and Boyle had built the CCD into the world's first solid-state video camera. In 1975, they demonstrated the first CCD camera with image quality sharp enough for broadcast television.

Today, CCD technology is pervasive not only in broadcasting but also in video applications that range from security monitoring to high-definition television, and from endoscopy to desktop videoconferencing. Facsimile machines, copying machines, image scanners, digital still cameras, and bar code readers also have employed CCDs to turn patterns of light into useful information.

It wasn’t until 1981, however, that Sony Corporation produced the first prototype digital camera, the Mavica (Magnetic Video Camera) electronic still camera, which recorded images as magnetic impulses on a compact two-inch still-video floppy disk. The images were captured on the disk by using two CCD (charge-coupled device) chips. One chip stored luminance information and the other separately recorded the chrominance information. This camera provided a 720,000-pixel image. The images could be stored on the floppy disk either in Frame or Field mode. When the photographer selected the Frame mode, the sensor recorded each picture on two tracks. Up to 25 images could be recorded on each disk.

When the photographer selected the Field mode, the camera recorded each picture on only one track, allowing up to 50 images to be recorded. Images were less detailed compared to images recorded in the two-track Frame mode. The MVC-5000 was considered to be the leader in image quality during its time. This was then put into a video reader that was connected to a television monitor or color printer. However, the early Mavica cannot be considered a true digital camera even though it started the digital camera revolution. It was a video camera that took video freeze-frames.

All this made the Mavica camera a bulky affair that looked more like a floppy disk box than a traditional camera. But, nevertheless, the race was on to see who could take this technology to new heights.

Unlike traditional cameras that use film to capture and store an image, digital cameras use a solid-state device called an image sensor. These fingernail-sized silicon chips contain millions of photosensitive diodes called photosites. In the brief flickering instant that the shutter is open, each photosite records the intensity or brightness of the light that falls on it by accumulating a charge; the more light, the higher the charge. The brightness recorded by each photosite is then stored as a set of numbers that can then be used to set the color and brightness of dots on the screen or ink on the printed page to reconstruct the image.

In 1986, Kodak scientists invented the world's first megapixel sensor, capable of recording 1.4 million pixels that could produce a 5x7-inch digital photo-quality print. In 1987, Kodak released seven products for recording, storing, manipulating, transmitting and printing electronic still video images. In 1990, Kodak developed the Photo CD system and proposed "the first worldwide standard for defining color in the digital environment of computers and computer peripherals." In 1991, Kodak released the first professional digital camera system (DCS), aimed at photojournalists. It was a Nikon F-3 camera equipped by Kodak with a 1.3 megapixel sensor.

Another significant model of camera, XapShot was a Hi-band still video camera. The XapShot had a built-in flash, self-timer, and an unusual rechargeable lead acid battery. Also required was a kit which included one floppy disk, the battery, and computer interface card with software. The American version of the XapShot could send a signal to a TV/VCR for playback and recording of images. There was also a very basic software utility that worked under System 6/7 for the Mac in conjuction with the a special video capture card that the camera connected to. Later, the Xapshot worked with Adobe Photoshop to capture the images.

In 1990, Logitech came out with the Dycam Model 1 black-and-white digicam, the world's first completely digital consumer camera. It stored 32 compressed images internally using 1MB RAM on a 376 x 240 pixel CCD at 256 shades of gray in TIFF format. This simple camera by today’s standards had an 8mm fixed-focus lens, standard shutter speeds of 1/30 to 1/1000 second and a built-in flash. The Dycam worked similarly to the XapShot except that it included the digitizing hardware in the camera itself. The user had to connect the camera to a PC to transfer images.

The first digital cameras for the consumer-level market that worked with a home computer via a serial cable were the Apple QuickTake 100 camera, which appeared in 1994. This camera featured a 640 x 480 pixel CCD which produced eight images stored in internal memory. It also had a built-in flash.

Unfortunately, having a tiny computer inside a camera presented problems in their exterior look. Since the camera’s onboard computer–essentially the CCD processor–too up so much space, early manufacturers like Fuji created square-shaped digital cameras. These were not only difficult to hold but required the user to learn a whole new way of using the device. But further miniaturizing of the camera’s sensor and, thus, it’s inner workings, led companies like Kodak, Nikon, Toshiba and Olympus to produce ever smaller cameras, and ones that a user could hold in much the same way as traditional cameras.

Today, just a little over 30 years after the invention of the original CCD sensor, digital cameras of all sizes and shapes–many of which now look similar to traditional 35mm cameras–are flooding the market.

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