A legacy format with RAW structure for storing photos taken with Canon cameras. It contains graphical information about data that was obtained through the lens without the use of hardware or software correction and compression. It contains metadata that identify shooting conditions and camera settings.
The G3 format is used to compress image files in TIFF format when sending faxes. The compression algorithm allows for the use of a standard 10-times compression, which can be increased. It is used to remove excess image data, which makes it possible to reduce the size of the image and speed up delivery.