OpenAnyFile
What is a .x3f file?
Sigma X3F RAW is a camera RAW format developed by Sigma / Foveon, first released in 2002. It is usually created by Sigma cameras with Foveon sensors.
Records three stacked colour layers per pixel from the Foveon sensor — not a Bayer mosaic, which is why most RAW converters cannot decode it.
File details
| Full name | Sigma X3F RAW |
|---|---|
| Category | Camera RAW |
| MIME type | image/x-sigma-x3f |
| Signature (magic bytes) | 46 4F 56 62 (FOVb) |
| Developer | Sigma / Foveon |
| Introduced | 2002 |
| Opens with | RAW preview extractor |
| Uploaded? | No — read locally in your browser |
How to open a .x3f file
OpenAnyFile routes .x3f files to its RAW preview extractor, which shows the full-size preview the camera embedded in the file.
- Drop your .x3f file on the box above, click it to choose the file, or paste it with Ctrl+V.
- The real format is detected from the file's first bytes — not just its name.
- The file opens in the RAW preview extractor.
- Use fullscreen for a closer look, check its checksums, or download it back unchanged.
What works — and what does not
Works
Viewing and inspecting: the full-size preview the camera embedded in the file. Size, type, signature and checksums are always shown.
Does not work
Editing layers or the raw data. You see the preview image stored in the file, not an editable document.
Is it safe to open a .x3f file online?
Here, yes — because nothing is uploaded. Most "online viewers" send your file to their server. OpenAnyFile reads it with your browser's File API and decodes it on your own device, so there is no copy anywhere else. You can check: open your browser's network tab while opening a file — no upload appears.
Questions about .x3f files
Can I open a .x3f file without installing software?
Yes. OpenAnyFile opens .x3f files in your browser using its RAW preview extractor. You get the full-size preview the camera embedded in the file, with nothing installed and no account.
How do I know a file is really a .x3f file?
Check its first bytes instead of its name. A genuine X3F file begins with 46 4F 56 62 (FOVb). OpenAnyFile shows the detected type, so a renamed file is easy to spot.
Is my .x3f file uploaded anywhere?
No. The file is read locally by your browser and never sent to a server — it even works offline once the page has loaded.
Does it work on phones?
Yes — on Android and iPhone, in any modern browser. You can also install OpenAnyFile as an app.
Related formats
Other formats from the same family:
Format facts checked and page updated on September 25, 2026.