Friday, July 13, 2007

Inside a Digital Camera

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 we all learned in grade school, there are three primary colors. Digital cameras use filters to divide the light into those three colors during the conversion process. Good quality cameras have three separate sensors for filtering, with each sensor matching one strand of light.

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.

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.

The potential size of the printed photographs is also decided by the camera's resolution. Because their resolution is relatively low, a 1-megapixel digital camera will produce images that are good for e-mailing or posting on the Web, and little else. The images taken by a 2-megapixel camera are suitable for 4x5 inch prints while good-looking 16x20 inch prints can be produced by a 4-megapixel camera. Better to get a 6 megapixel or higher model if you love working with photos.

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.

Wilfred Ursley is a writer for a variety of popular Internet magazines, with information on consumer electronics and alternative health subjects.
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