To be clear, they default to JPEG for the image preview on the monitor (LCD screen). Whenever viewing an image on a professional camera, you’re always seeing the resulting JPEG image.
The underlying data is always captured as a RAW file, and only discarded if you’ve configured the camera to only store the JPEG image (discarding the original RAW file after processing).
The underlying data is always captured as a RAW file, and only discarded if you’ve configured the camera to only store the JPEG image (discarding the original RAW file after processing).