Two things are worth knowing about Olympus Raw before you try to open one. The extension survived the brand change from Olympus to OM System.
| Signature | 49 49 2A 00 at offset 0 |
| Written by | OM Digital Solutions (formerly Olympus) |
| Extension | .orf |
| Full name | Olympus Raw |
What is actually stored
TIFF-based container with Olympus maker notes and a 16-bit mosaic; the preview JPEG is stored as a separate IFD.
The first bytes
The check is cheap: the first 4 bytes are 49 49 2A 00. If anything else is sitting at offset 0, the file was renamed and the extension is the problem, not the file.
When the same file behaves differently on two machines, the file is usually fine and the reader is not. Compare the two readers before blaming the file.
Opening it without the program that made it
Installed options: OM Workspace, Olympus Viewer, Adobe Camera Raw, Darktable, RawTherapee, capture one. None of them have to be the program that made the file: Universal Viewer reads it and writes nothing back.
When you have to convert
The targets people actually ask for are .jpg, .png, .dng, .tif. Each one has its own page with the settings that matter: orf → jpg, orf → png, orf → dng, orf → tif
M. Halvorsen re-read this on 2026-10-05.
Notes from the file library
Files of this kind are catalogued with the family named in the table above. The family groups them by what a file carries, not by the application that wrote it, which is why two extensions from the same application can sit in different families.
Two things decide whether a file can be opened on a machine that never had the application that made it: the header, which says what the container is, and the structure behind it, which says whether the contents can be read at all. The conversion guides listed on the page cover the targets that come up most often.
Format pages are rebuilt with each release of the toolset, and the review line at the bottom of the page is when an editor last checked the entry against a file. If a page disagrees with a file you have, send the first sixteen bytes and the build number to the support address and the entry is corrected in the next build.