What is an X3F file?

X3F is Sigma's RAW format, used exclusively with Foveon X3 sensor cameras including the SD9, SD10, SD14, SD15, SD1 / SD1 Merrill, DP1/DP2/DP3 Merrill compacts, the dp Quattro series (dp0/dp1/dp2/dp3 Quattro), and the sd Quattro and sd Quattro H. The Foveon sensor stacks red, green, and blue photosites vertically (unlike Bayer-pattern sensors which mosaic them horizontally), producing files with unusual color fidelity but heavy noise above ISO 400. Landscape photographers chasing Foveon's near-medium-format sharpness at 35mm price points are the primary X3F audience converting to JPG.

Sigma Photo Pro (free from sigma-global.com) is the only software that fully processes X3F because the Foveon demosaicing isn't actually demosaicing - it's a per-layer color separation Sigma developed in-house. Lightroom can open X3F via LibRaw but applies a Bayer-style algorithm that produces softer, less colorful output than SPP. Foveon enthusiasts always process in SPP, export 16-bit TIFF, then derive JPG quality 95 for sharing - the SPP look (deep blues, painterly skin, high acuity) is the entire reason to shoot Foveon.

Landscape and architecture photographers who don't need fast autofocus or video and value Foveon's signature rendering convert X3F to JPG for portfolio sites, fine-art print sales, and gallery submissions. The dp0 Quattro's 21mm equivalent ultra-wide produces 39MP-equivalent X3F files around 50MB; SPP-processed JPG at quality 95 lands around 12-18MB, retaining the Foveon detail that makes 30x40-inch prints look like medium-format work despite the small sensor footprint.

Reasons to convert X3F to JPG usually come down to compatibility, file-size, or specific feature requirements. Common situations:

• An app or platform only accepts JPG uploads.
• You need a feature unique to JPG (e.g. transparency, vector scaling, animation, multi-page pages, etc.) that X3F doesn't provide.
• You're optimising file size — modern formats often produce smaller files than the older format you started with.
• You need a single archival format across a project so files behave consistently in the same viewer.

1. Open the X3F → JPG tool on jpg.now.
2. Drag your X3F file onto the drop zone, or click Select files. You can drop a whole folder of files at once.
3. The output is fixed to JPG. If the format supports extra options (page size, transparency background, quality, EXIF stripping), tweak them in the right-hand panel.
4. Click Convert. The job runs on our server and finishes in a few seconds for typical photos.
5. Download the result. Files stay in storage for 24 hours and are then permanently deleted.

The entire flow is free for the first 10 jobs per day with no signup required. A free account doubles that quota; a premium plan removes the limit entirely.

• Use Sigma Photo Pro for processing - the Foveon sensor's vertical RGB stacking requires Sigma's proprietary algorithm to reveal the format's color signature.
• Stay below ISO 400 on Foveon - chroma noise above ISO 800 becomes uncorrectable; convert these higher-ISO X3F files to monochrome JPG instead.
• Apply SPP's X3 Fill Light at +0.3 to +0.7 to recover Foveon's notoriously dark shadows without introducing the green cast Bayer-style shadow lifting causes.
• Quality 95 is the right JPG export level - Foveon files don't compress as efficiently as Bayer because of the layered color data, so go higher than usual.
• Strip lens info from EXIF if you shot a Foveon adapter with non-Sigma glass - the metadata often confuses cataloging software that expects Sigma-only lens IDs.