X3F to HEIF Converter

How to Convert X3F to HEIF Online

1. Upload Your X3F File: Drag and drop or click "+ Add Files" to select Sigma X3F RAW files from an SD9, SD10, SD14, SD15, SD1 Merrill, DP/dp Merrill, or DP/dp Quattro camera. Batch uploads are supported.
2. Pick a Quality Preset: The default is Very High (Recommended) under Image Compression. Drop to High or Medium to shave more bytes off the HEIF for messaging and email, or stay at Very High to preserve the Foveon sensor's per-pixel color detail for archival storage.
3. Set Resolution (Optional): Leave Resolution Percentage at "Keep original" to retain the camera's native pixel count, pick a Preset Resolution (4320p down to 144p), or enter a custom Width, Height, or Width x Height while keeping aspect ratio.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

Why Convert X3F to HEIF?

X3F is Sigma's proprietary RAW container, written by cameras that use the Foveon X3 stacked-photodiode sensor — a three-layer design (introduced with the Sigma SD9 in October 2002) that captures red, green, and blue at every pixel location instead of demosaicing a Bayer mosaic. The files are large, slow to render, and only fully understood by SIGMA Photo Pro, dcraw, Iridient Developer, and a small handful of third-party readers. HEIF (ISO/IEC 23008-12), standardised by MPEG in 2015, is roughly half the size of JPEG at matched visual quality and natively supports 10-bit and 12-bit depth, wide colour, and alpha — so it's a far better delivery format than JPEG once you've finished editing the RAW.

• Send photos without the RAW penalty. A 50 MB X3F from a 46 MP dp Quattro becomes a 2-4 MB HEIF at Very High quality, easily small enough for iMessage, Signal, or a Gmail attachment (25 MB cap).
• Hand files to non-Sigma users. Anyone on iOS 11+, macOS High Sierra+, Windows 10 (with the HEIF Image Extensions installed), or Android 9+ can open HEIF without buying or installing Sigma's processing app.
• Keep more colour fidelity than JPEG. HEIF preserves 10-bit gradients, which matters for the smooth tonal transitions the Foveon sensor is prized for — JPEG truncates those to 8-bit and bands the skies.
• Save iCloud and Google Photos storage. Sharing the HEIF instead of a baked TIFF or maximum-quality JPEG roughly halves your cloud footprint per image.
• Faster preview on modern devices. iPhones, iPads, M-series Macs, and recent Pixel phones decode HEIF in hardware via their HEVC blocks; X3F has no hardware decoder anywhere.
• Better archival than JPEG. When you keep the original X3F as your master, HEIF is a higher-quality, smaller "view copy" than a JPEG export.

X3F vs HEIF — Format Comparison

Quality Preset Guide

Frequently Asked Questions

What's the difference between HEIF and HEIC, and which does this converter produce?

HEIF (ISO/IEC 23008-12) is the container; HEIC is Apple's specific subset that mandates the.heic extension and HEVC-encoded images. This page outputs a .heif file using HEVC, which Apple Photos, Preview, and Finder treat identically to a.heic file. If you specifically need the .heic extension (some Apple workflows match on it), use Convert X3F to HEIC instead.

Will I lose RAW editing latitude when I convert to HEIF?

Yes. X3F holds the unprocessed per-layer Foveon sensor data, so you can recover blown highlights, push shadows several stops, and re-set white balance non-destructively. HEIF stores a baked, demosaiced image — quality is high, but the exposure, white balance, and contrast you see at conversion time are what you keep. Always retain the original X3F as your master and treat the HEIF as a delivery copy.

Why is my HEIF smaller than a JPEG export of the same X3F?

HEIF wraps HEVC-encoded intra frames, and HEVC compresses still images roughly 40-50% more efficiently than JPEG at matched perceptual quality (the ISO/MPEG reference figure is JPEG needing about 2.39× the bits of HEVC for the same objective quality). You get the same picture in roughly half the bytes.

Which Sigma cameras produce X3F files this tool can read?

Every Foveon-sensor Sigma DSLR and mirrorless writes X3F: SD9 (2002), SD10, SD14, SD15, SD1, SD1 Merrill, the DP1/DP2/DP3 Merrill compacts, and the dp0/dp1/dp2/dp3 Quattro models. The fp and fp L use a Bayer sensor and write DNG instead, not X3F.

Will the embedded JPEG preview be used, or is the Foveon data re-rendered?

The converter decodes the full Foveon sensor data rather than just extracting the embedded thumbnail, so you get the camera's actual capture resolution (e.g. ~5424 x 3616 from a dp Quattro), not a low-res preview pulled from the header.

Does my Foveon colour signature survive the conversion?

The characteristic Foveon look comes from per-pixel three-layer colour capture. Once demosaiced into a standard RGB image, that signature is largely retained in the pixels themselves — HEIF then preserves them at 10-bit depth with very little additional loss. You won't get more Foveon character by converting, but you won't lose what's in the rendered image either.

Where can HEIF files be opened?

iOS 11+ and iPadOS, macOS 10.13 High Sierra and newer, Windows 10/11 with the free HEIF Image Extensions from the Microsoft Store (HEVC Video Extensions is also needed for HEIC/HEIF created by Apple devices), Android 9+, modern Chrome and Edge (via OS codecs), Photoshop 2023+, Affinity Photo, and GIMP 2.10+ with the heif plugin. Safari supports HEIF natively on macOS and iOS.

Can I batch-convert a folder of X3F files at once?

Yes — drag the whole folder into the upload area and every X3F file will be processed with the same Quality Preset and Resolution settings. Each file is downloaded as its own .heif.

What if I need a TIFF or JPG instead of HEIF?

Use Convert X3F to JPG for the most universally compatible output (any browser, any OS, any photo app) or Convert X3F to TIFF for a 16-bit lossless editing intermediate suitable for Photoshop, Lightroom, or Capture One.