The following is a Plus Edition article written by and copyright by Dick Eastman.
If you have a digital camera with advanced features, and if you have a photo editing program with advanced features, and if you have plenty of disk space on your hard drive, I'd suggest that you create your photos in RAW format.
What is RAW?
This is one time in technology when a 3-letter term is not an abbreviation or acronym for three words. In this case, RAW is just that: raw, unprocessed, unrefined, unchanged, original. In this case, RAW means that the image is just as the camera saw it; the picture has not yet been processed by the camera.
Most digital camera owners do not realize that, when they push the shutter, the camera takes the picture, PROCESSES IT, and then stores the processed image in the camera's internal memory card or whatever media is used. The picture stored inside the camera is actually quite different from what the camera saw and, for simpler applications, that is a good thing.
When you push the shutter on your digital camera, a lot of things happen very quickly. The lens opens, and the image sensor is exposed to light. The image sensor is a device that converts an optical image to an electric signal. The sensor captures light and converts it into electrical signals.
The interesting thing is that the image sensor doesn't see light in the same way that you and I do. That is, an image sensor doesn't see bright greens as greens and pinks as pinks. In addition, the brightness may not be the same to an image sensor as it is to a human eye. A section of the photograph may seem brighter or darker to an image sensor than it does to us humans.
The default setting on most digital cameras is to send the newly-captured signal through some electronics to convert the image to something close to what the human eye sees, then save the output of that conversion process. A very complex process called demosaicing first determines the color of each pixel. The resulting color image is then adjusted in various ways, including being white balanced to compensate for the type of light you were shooting in. Then the image is sharpened, compressed so that it doesn’t take up as much space, and finally stored on your memory card. Most of today's digital cameras will store the image in JPEG (or JPG) format, which has already been compressed and (sometimes) has already lost a bit of the original sharpness.
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