Add your X3F file
Drop one or more .x3f files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
X3F to APNG
Developing a .x3f camera file into .apng turns unprocessed sensor data into a finished image any app can open. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop X3F files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Sigma RAW to Animated PNG
Developing a .x3f camera file into .apng turns unprocessed sensor data into a finished image any app can open. An .x3f file is a Sigma RAW photograph captured with a Foveon X3 sensor, which stacks three photodiode layers so every pixel location records red, green, and blue directly. That architecture makes .x3f fundamentally different from Bayer-pattern RAW files — there is no color mosaic to demosaic — and gives Foveon images their reputation for peculiar, film-like per-pixel sharpness.
An .apng file is an animated extension of PNG: full 24-bit color with 8-bit alpha per frame, in a stream that plain PNG decoders read as a normal still image. It delivers the smooth, semi-transparent animation that GIF's 256-color palette never could, and it is the format behind many messaging-app sticker packs. For this route the practical draw is 16.7 million colors and real alpha per frame, versus GIF's 256 and binary transparency and backward compatible: old decoders still render the first frame — balanced against files grow quickly for long or high-motion animations, where animated WebP/AVIF or video compress far better, which is worth knowing before you commit a large batch.
Why convert X3F to APNG?
The practical trigger for this conversion is usually a mismatch: with .x3f, third-party support is the weakest of any major RAW format; Sigma Photo Pro is often the only full-fidelity path. Switching to .apng buys you 16.7 million colors and real alpha per frame, versus GIF's 256 and binary transparency, which is why it is the better fit for animated stickers (Apple's iMessage and LINE both build on APNG). Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
X3F vs APNG at a glance
| Aspect | Sigma RAW (.x3f) | Animated PNG (.apng) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Lossless — every pixel or sample is preserved exactly |
| How it stores data | records three stacked layers per photosite, exploiting silicon's wavelength-dependent light absorption instead of a color filter array | adds three chunk types to PNG: acTL (animation control), fcTL (frame control), and fdAT (frame data) |
| Strongest at | base-ISO landscape, product, and architecture work where Foveon detail shines | animated stickers (Apple's iMessage and LINE both build on APNG) |
| Weak spot | third-party support is the weakest of any major RAW format; Sigma Photo Pro is often the only full-fidelity path | files grow quickly for long or high-motion animations, where animated WebP/AVIF or video compress far better |
Pick APNG as the output
Select .apng in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if APNG is selectable, the route is real and validated.
Convert on your device
Press Convert. A LibRaw WebAssembly decoder demosaics the sensor data in your browser and renders a developed image ready for export.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid APNG file. Outputs keep the original filename with the .apng extension.
X3F to APNG questions, answered
Will converting X3F to APNG lose quality?
Since x3f is lossless-oriented and apng is lossless-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .apng itself requires.
Is it private to convert X3F files here?
Yes — the .x3f file is processed inside your browser tab and never uploaded. A LibRaw WebAssembly decoder demosaics the sensor data in your browser and renders a developed image ready for export. Close the tab and the file is gone from memory.
Where will the APNG file work?
Chrome 59+, Firefox 3+, Safari 8+, and Edge 79+ all animate .apng natively, so browser coverage is complete. Desktop support is patchier — most image editors open only the first frame — and social platforms frequently flatten or re-encode uploads, so test the target platform before committing to it.
Will the APNG file be bigger or smaller than my X3F?
It depends on the content: adds three chunk types to PNG: acTL (animation control), fcTL (frame control), and fdAT (frame data). Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my X3F file?
In .x3f, eXIF fields and Sigma's property lists are embedded in the container, but MakerNote conventions differ enough from Bayer vendors that generic tools extract less; ExifTool provides the most complete parsing. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.