If you use a digital camera, it can help to have a little deeper understanding how these modern wonders work. Briefly, digital cameras have a series of lenses that focus light onto a sensor instead of film. The sensor electronically records the image, and transfers it to the "brains" of the camera. Here it is organized and then converted into binary data, so it can be stored in memory or on removable memory units for later reading by a computer or printer.
Most digital cameras' sensors are charge-coupled devices, or CCDs, although some cameras instead have a complementary metal oxide semiconductor, or CMOS. Either way, light is converted into electrical charges, which are transferred to the brain, and finally onto the storage media.
As part of this process the sensors filter the light into the three primary colors, which can be combined to create the full spectrum. The more expensive (and higher quality) cameras use three separate sensors to accomplish this task. Each sensor is fitted with a filter of a different color, making it read only the light that matches that color.
Digital cameras also control the amount of light that actually reaches the sensor. They do this through the aperture or hole size, and through the shutter speed. Most cameras have automatic aperture setting though some do allow for manual control, which is preferable for professional photographers and advanced amateurs. Shutter speed is set electronically.
There are four kinds of lenses used by digital cameras: optical-zoom lenses with automatic focus; fixed-focus, fixed-zoom lenses; digital-zoom lenses; and replaceable lens systems. Optical zoom lenses have both telephoto and wide options, while the fixed focus and fixed zoom lenses are used in the ordinary, inexpensive cameras that infrequent users own. The digital zoom lens creates the illusion of a zoom effect by culling pixels from the central part of the image and enlarging them to fill the frame. This, however, often results in a grainy or fuzzy image at the extreme limits of the camera's capabilities.
An LCD screen is standard on most digital cameras today, and they help in previewing images and also checking them out after taking a shot. Many screens are rather small, because there is only so much space on a camera for them. It is always best to transfer the images to a computer for viewing. In terms of image quality in general, the higher resolution the camera, the better the image quality.
For printing photos, resolution of the original image is also key. A low quality camera such as those found in many cell phones will create images that are really only useful for emailing or for web pages. A 2-megapixel camera produces images that can be blown up to about 4x6 inches. Four megapixels will create nice 16x20 inch images, but with falling prices on most digital cameras, if you enjoy photography and enlarging photos, don't settle for less than six megapixels.
Early digital cameras stored images on memory resources built into the camera. Images were then transferred to computers with the help of cables. Most modern digital camera makers utilize reusable and removable storage devices. These devices include SmartMedia cards, CompactFlash cards and other memory sticks. Other, less common removable storage devices include hard disks or microdrives, and writeable CDs or DVDs. These options have considerably enhanced the volume of visual data that can be stored as well as the overall flexibility of the modern digital camera.
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