Inside a Digital Camera
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.
The most common digital camera sensor is a charge-coupled device, or CCD, but some models use a complementary metal oxide semiconductor (CMOS). In either case, light beams are converted to electrical charges, which are then transferred to the core electronic section, and eventually 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.
The amount of light reaching the sensor is also controlled carefully. Cameras do this in two ways: aperture size, and shutter speed. Most of today's cameras have automated aperture settings, although some models allow manual control, which enthusiasts and professionals prefer. Shutter speed is generally set electronically.
There are four main types of lenses for digital cameras: fixed focus, replaceable lens systems, fixed zoom, and digital zoom. Less expensive cameras typically have fixed focus or fixed zoom lenses. Digital zoom lenses have a way of enlarging the pixels from the middle of the image, rather than actually zooming in on an object in the distance. Therefore, they tend to make images grainy or fuzzy, unlike the much more cleanly zoomed images that an optical zoom lens can produce.
Most digital cameras come with an LCD screen to preview images or to look at them after capture. Most LCD screens are rather small, because the size of the cameras overall is small, too. For better viewing, you must transfer the image to a computer. For quality of image, the biggest factor is the resolution, which is measured in megapixels. The higher the resolution, generally the better the image quality.
Resolution also plays a role in the quality and size of the printed photographs. A cell phone camera or other low quality camera with a one megapixel resolution will produce images that are really only good for emailing or web pages, not printing. With a 2-megapixel camera, the images are good for printing at 4x6 inch sizes or so, while a 4-megapixel camera can be detailed enough to produce good prints at 16x20 inch size. With prices falling continually, if you love photos and hope to make some enlargements, you are best to only consider cameras above 6-megapixels.
In the early days of digital cameras, images were stored on fixed memory locations built into the device. When it came time to transfer images, you needed a cable to attach to your computer. Today, removable memory storage is the way to go, as the flexibility and convenience of the camera is enhanced. And reusable memory means you can enhance the amount of data you can comfortably keep with the camera -- more pictures and higher resolution pictures. Removable memory is stored on various devices such as CompactFlash cards, SmartMedia cards, and other memory sticks. Some cameras use small hard drivers, called microdrives, or burnable DVDs. No matter what you choose, having a digital camera is fun, and frees you from the costs of film.
Wilfred Ursley writes for several popular Internet magazines, with tips and resources on consumer electronics and alternative health subjects.
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