Digital Cameras use lenses and a shutter to capture light inside the body of the camera just like traditional film cameras, but that is where the similarity ends.
Instead of using film to capture an image as the traditional cameras do, the digital camera captures the image using an image sensor.
These sensors are completely electronic in their operation. They have various internal electronic devices to measure light intensity and a host of other duties.
The complexity of the image sensor determines its rating, measured in MegaPixels. The higher the number of megapixels that a digital camera offers, the greater the clarity and quality of the resulting picture. Also the higher the megapixel rating of the digital camera, the higher the cost of the camera.
Digital cameras function by converting light into an electrical signal that is, in turn, converted into binary (1’s and 0’s) so they can be processed through the digital camera’s on-board computer. After the binary numbers are processed they are stored on the digital memory card or floppy disk.
The digital camera processes the light in such a way that the light is converted into the primary colors of Red, Green and Blue using internal filters. The photographs must be further refined by computer processing to produce the full color photograph. This process is called Demosaicing.
Many cameras offer photo sharpening to make the digital photographs clearer; usually, there are controls on the digital camera to adjust brightness, contrast, and color saturation.
After all this is done — inside the digital camera — the last step is to compress the image and then store it on the memory card.
To load images from a digital camera onto a computer and give you the ability to process the digital picture manually, requires a digital camera that offers this cability. If you would like this feature you should ask if the camera you are considering includes it before making your purchase.