Digital Camera Basics
In terms of handling, Digital Cameras are more or less the same as the film cameras. Both of them have a lens for focusing on specific images, a shutter for letting light inside the camera and also an aperture for controlling the amount of light entering the camera. Therefore, the main difference between digital photography and the traditional photography happens to be the time and process involved after light enters the camera. While the traditional camera captures its images on film, a digital camera captures its images on an image sensor.
Image Sensors
Image Sensors are, in fact, electronic devices that are made up of electrodes or photosites arranged in an array which calculate the intensity of light. The most popular, universally recognised and commonly used types of image sensors are the CCD [Charge Coupled Device] and the CMOS [Complementary Metal Oxide Semiconductor] sensors, both of which use different technologies to capture images digitally. The number of photosites featuring in an image sensor gives the megapixels rating (millions of pixels) for a digital camera. Each photosite represents a pixel in terms of the final image. Therefore, a digital camera with a six megapixels rating would mean 6 million megapixels. When light goes on to hit the image sensor, it gets converted into electrical signals that are built and fed to an A/D converter [Analog to Digital]. The A/D converter, then, changes electrical signals into binary numbers for processing by a computer that is housed in the camera body itself, which, then, stores the resulting images in memory cards.
Coloured Images
However, Photosites can, just about, measure only the intensity of light but not the colour, as such. Hence, for producing colour images, each of the photosites need to be covered with red, green or blue colour filters. But, since they can be covered with only one coloured filter at a time, computer processing is essential for producing a full coloured image. This is done by a process that analyses a certain pixel along with its immediate neighbours for producing a full coloured image with composite colours. This entire process is called as demosaicing.
Image Compression
After demosaicing, images are adjusted according to the camera settings for colour saturation, contrast and brightness while some digital cameras apply sharpening algorithms for making images clearer. The final step towards saving images on to the memory card is Compressing the image. Most digital cameras make use of the JPEG compression format. This reduces the file size while eliminating excess data. The eliminated data cannot be recovered and hence, JPEG is also referred to as the lossy format. Most digital cameras also have the ability for saving uncompressed images as RAW data or TIFF files. RAW data refers to the original photosite data before even demosaicing which then is processed through a special software in your digital camera with much greater controls.
Conclusion
Digital Cameras allow you to shoot countless photographs, see, download and print them instantly and are wonderful gadgets since they involve low costs in terms of buying and owning one. Digital photography has, over time, evolved for the good. Plenty of advancements in this field have happened and are still happening by the day, catapulting digital photography to great heights in today’s world.
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