About camera raw files

Camera raw image file formats are like digital negatives. They are created by a variety of digital cameras and contain all the information the camera has about the image. The image information is directly captured from the camera's Charged Coupled Device (CCD) or Complementary Metal-Oxide Semiconductor (CMOS) without filters and adjustments applied by the camera. This lets photographers interpret the image data rather than letting the camera make the adjustments and conversions.
Similar to TIFF, a camera raw image file does not throw away any image information to generate a file--it's lossless--but camera raw image files have the advantage of being smaller than uncompressed TIFFs. Only camera raw images contain the actual data captured by the sensor without any in-camera processing.