On the heels of the Canon C500 being shipped, AbelCine explains what Canon Raw is. They write, "Canon Raw is unlike any Raw format that we’ve seen before. Canon has a very unique Raw method that deserves some explaining, but first – what is it? Canon Raw is stored in file stacks, similar to ARRIRAW or CinemaDNG, and each frame is in an .RMF (Raw Media Format) file. Any given take will be stored in a folder containing stacks of these files. Each frame is approximately 11MB in size, making it larger than just about any Raw format out there."
Read their full post here.