X3F to PNG Converter

How to Convert X3F to PNG Online

1. Upload Your X3F File: Drag and drop or click "+ Add Files" to load the Sigma RAW files straight from an SD card or local folder. Batch upload is supported — a full SD Quattro shoot can go in one pass. Files stay on our servers; nothing is sent to a third-party RAW processor.
2. Pick a Quality Preset: Default is Original quality, which writes a full-fidelity PNG with the demosaiced Foveon data intact. Pick a lower preset to trade detail for size, or leave it on Original for archival and print work where the whole reason to leave X3F is to lock in the pixels you already shot.
3. Set Resolution, Colors, and Compression (Optional): Choose an Image resolution preset (4K, 1080p, 720p, etc.), enter a custom width/height, or scale by a percentage — useful when the source is a 46 MP Merrill frame and you only need a 2,400-pixel web image. Drop the Colors palette to 256, 64, or 16 if you need a small indexed PNG for icons. Push Compression level higher (slower) for smaller files, or lower (faster) when you have hundreds of frames to chew through.
4. Convert and Download: Click "Convert" and grab each PNG individually or as a ZIP. No Sigma Photo Pro install, no sign-up, no watermark.

Why Convert X3F to PNG?

X3F is Sigma's proprietary RAW container for cameras built around the Foveon X3 sensor — a three-layer silicon stack that records red, green, and blue at every photosite rather than interpolating them from a Bayer mosaic. The format first shipped with the Sigma SD9 in 2002 and stayed through the Merrill (46 MP equivalent) and Quattro (39 MP Bayer-equivalent, 1:1:4 layer ratio) generations. The trade-off is that almost nothing outside Sigma Photo Pro, dcraw, and a handful of third-party tools opens it natively — so once you've picked your keepers, exporting to PNG turns the file into something every browser, OS, and image editor can read losslessly.

• Send proofs that don't need RAW software — Clients, art directors, and stock-agency reviewers shouldn't have to install Sigma Photo Pro just to view a frame. A 16-bit PNG preserves the full tonal range without forcing a JPEG re-encode.
• Web galleries and portfolio sites — PNG is supported in every major browser (Chrome, Firefox, Safari, Edge) and the format has been an ISO/IEC standard (15948) since 2003. Foveon's clean per-pixel color survives the export better than JPEG's chroma subsampling.
• Print prep without a destructive JPEG step — When you hand a file to a print shop, an 8-bit-per-channel PNG at 300 DPI keeps the Foveon micro-detail intact and avoids the visible posterisation a low-quality JPEG can introduce on smooth skin or skies.
• Archive a frozen rendering — X3F demosaicing changes as RAW processors update; saving a PNG locks in the look you approved today so a future Sigma Photo Pro release can't "improve" your edit out from under you.
• Compatibility with editing pipelines — Photoshop, GIMP, Affinity, and almost every web CMS accept PNG without a plug-in. The Sigma X3F Photoshop plug-in exists but requires a manual install and isn't kept current for every PS release.
• Transparency support — PNG's alpha channel lets you mask out backgrounds for product shots or composites — something the X3F source can't carry on its own.

Need a different output? See X3F to JPG for smaller share-ready files, X3F to TIFF for 16-bit print masters, or X3F to PDF for proof sheets. Already have PNGs and want them smaller? Run them through Compress PNG.

X3F vs PNG — Format Comparison

X3F-to-PNG Output Recipes

Frequently Asked Questions

Why convert X3F instead of just keeping the RAW?

X3F is only safe to keep if you (and everyone you share with) have a current copy of Sigma Photo Pro, dcraw, or LibRaw. PNG is readable by every browser and OS, including ones that won't ship with X3F support a decade from now. Most photographers keep the X3F as their archival negative and export a PNG (or TIFF) as the deliverable.

Will I lose Foveon's per-pixel colour detail in PNG?

No — once the X3F has been demosaiced, the three-channel RGB result is preserved exactly by a lossless PNG. The catch is that demosaicing happens at conversion time, so a different RAW processor on a different day may render slightly different colour. Save a 16-bit PNG (rather than 8-bit) if you want the most tonal headroom for later edits.

Does the converter use Sigma Photo Pro to demosaic?

No — the conversion uses an open-source X3F decoder pipeline (LibRaw-style) running on our servers, so you don't need Sigma Photo Pro installed. The trade-off is that very early X3F files from the SD9/SD10 era and some Quattro-specific metadata are less battle-tested than they would be in Sigma's own software. If you see colour shifts on those frames, run them through Sigma Photo Pro first and export to TIFF.

Why is my PNG larger than the X3F it came from?

X3F stores compressed sensor-side data (one value per photodiode, three diodes per pixel). When you demosaic and write to PNG you produce full RGB (or RGBA) data for every pixel, which can be larger — especially at 16-bit. Drop to 8-bit, use a smaller resolution preset, or accept the larger file as the cost of a universally readable output.

Will the embedded JPEG preview in the X3F be used?

No — that preview exists for in-camera review and quick thumbnails, and using it would throw away the whole point of shooting RAW. The converter demosaics the full Foveon data so your PNG reflects the actual sensor capture, not the camera's JPEG-engine guess.

Can I keep the EXIF (camera, lens, ISO, date)?

Yes for the most common tags — camera model, lens, ISO, shutter speed, aperture, and capture date are read from the X3F and written into the PNG's tEXt/eXIf chunks where supported. Some Sigma-specific maker notes (white-balance fine-tuning, custom film modes) don't have standardised PNG equivalents and are dropped.

Should I pick PNG or TIFF for archival?

TIFF is the traditional choice when you want 16-bit-per-channel data plus layers and the widest editor support. PNG is a lighter, universally browser-readable alternative that still supports 16-bit and lossless compression. For a viewer-first archive, pick PNG. For a "this file will live in an editor stack later" archive, pick X3F to TIFF.

Which Sigma cameras produce X3F files this tool handles?

Any Sigma body using the Foveon X3 sensor: SD9 and SD10 (early 2000s), the SD14/SD15/SD1 line, the DP1/DP2/DP3 fixed-lens compacts, the Merrill generation (46 MP equivalent), the Quattro generation (39 MP Bayer-equivalent with the 1:1:4 layer ratio), and the SD Quattro / SD Quattro H. Files from third-party tools that have re-wrapped X3F may have lost metadata the decoder needs.

What if my X3F file is over the upload size?

Modern Quattro and Merrill X3F files are typically 45-75 MB each; that's well inside the converter's per-file ceiling. If a frame is unusually large (HDR bracket re-saved as one file, for example), split or re-save it from Sigma Photo Pro first. For multi-gigabyte shoots, upload in smaller batches rather than one giant queue.