A file with the extension .ORF is associated with a RAW image file taken with an 'Olympus' digital camera'.
A 'RAW' image file contains only minimally processed data taken via the sensor of the digital camera.
The purpose of this is that settings such as: exposure, white balance, etc. can then be modified later as desired.
* Different .ORF files (with different formatting) are produced by different Olympus cameras, it is advisable to check that your particular camera model is supported before using/purchasing photo editing software.
The .ORF file extension is known to be supported by the following models: