How Do Digital Cameras Work?
Digital cameras have now fully completed their coup of the camera industry. If you recently got one yourself, it can be useful to have a bit more understanding of how they work. Simply put, digital cameras contain a lens or series of lenses that allow light passing through them to focus on a sensor, rather than traditional film. The sensor then transfers the image data to the core electronics of the camera, where it is organized and converted into binary forms of data. Thus it can more easily be stored onto reusable memory units for later viewing by a computer.
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.
Lenses for digital cameras come in four varieties: digital-zoom lenses; fixed-zoom lenses; replaceable lens systems; and fixed-focus. Fixed lenses, both zoom and fixed focus, tend to be found in the cheaper cameras. Optical zoom lenses can have both wide angle and telephoto options. Digital zoom lenses don't actually zoom a piece of glass, but rather take pixels from the central part of the image, and enlarge them. This appears to be a zoom, but if you look closely, you will notice that they are more grainy or fuzzy images than you get without invoking the zoom option.
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.
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.
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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