SOURCE
ORF
Olympus RAW Format comes from Micro Four Thirds bodies such as the OM-D E-M1, E-M5 and E-M10, the PEN range and the newer OM System OM-1 and OM-5. The files are smaller than full-frame RAW because the sensor is smaller. Olympus Picture Modes and Art Filters are applied in the camera's JPEG only, not to the ORF data.