A camera RAW image is an unprocessed photograph captured with a digital camera. It contains the raw image data captured by the camera's sensor (or CCD), saved in proprietary file format specific to the camera manufacturer.
By default, most digital cameras process and compress photos as JPEG files immediately after capturing the image. The processing step automatically applies the appropriate color correction and the JPEG compression significantly reduces the file size. The result is an efficiently processed JPEG image.
While JPEG images are suitable for most purposes, professional photographers and photography enthusiasts prefer to control over how each image is processed. Therefore, many high-end cameras have the ability to shoot in RAW mode instead of JPEG. The raw files are unprocessed, allowing the photographer to adjust settings like exposure, white balance, and saturation after the image has been captured. Instead of applying lossy JPEG compression, which reduces the image quality, RAW mode saves files in a losslessly compressed format.
Viewing Camera RAW Files
Since Camera RAW files are not saved in a standard image format, image viewing programs may not recognize them. Even if a program supports the Canon RAW format, it may not recognize a RAW file saved by a newly released Canon camera. Therefore, camera manufacturers often include proprietary RAW photo editing software with their high-end cameras. Additionally, popular operating systems and software programs are regularly updated with support for new RAW formats.