The digital camera is one of the most remarkable advances of the modern day. While Conventional cameras depend entirely on chemical and mechanical processes -- you don`t even need electricity to operate them. On the other hand, all digital cameras have a built-in computer, and all of them record images electronically. The new approach has been enormously successful. Since film still provides better picture quality, digital cameras have not completely replaced conventional cameras. But, as digital imaging technology has improved, digital cameras have rapidly become more popular.

At its most basic level, this is all there is to a digital camera. Just like a conventional camera, it has a series of lenses that focus light to create an image of a scene. But instead of focusing this light onto a piece of film, it focuses it onto a semiconductor device that records light electronically. A computer then breaks this electronic information down into digital data. All the fun and interesting features of digital cameras come as a direct result of this process.

Instead of film, a digital camera has a sensor that converts light into electrical charges. The image sensor employed by most digital cameras is a charge coupled device (CCD). Some cameras use complementary metal oxide semiconductor (CMOS) technology instead. Both CCD and CMOS image sensors convert light into electrons. A simplified way to think about these sensors is to think of a 2-D array of thousands or millions of tiny solar cells.

Once the sensor converts the light into electrons, it reads the value (accumulated charge) of each cell in the image. This is where the differences between the two main sensor types kick in:

A CCD transports the charge across the chip and reads it at one corner of the array. An analog-to-digital converter (ADC) then turns each pixel`s value into a digital value by measuring the amount of charge at each photosite and converting that measurement to binary form.

CMOS devices use several transistors at each pixel to amplify and move the charge using more traditional wires. The CMOS signal is digital, so it needs no ADC.

Interesting Facts

• With a 3-megapixel camera, you can take a higher-resolution picture than most computer monitors can display.



• You can use your Web browser to view digital pictures taken using the JPEG format.



• The first consumer-oriented digital cameras were sold by Kodak and Apple in 1994.



• In 1998, Sony inadvertently sold more than 700,000 camcorders with a limited ability to see through clothes.