X3F to ASF Converter

How to Convert X3F to ASF Online

1. Upload Your X3F Files: Drag and drop or click "+ Add Files" to select X3F raws from a Sigma SD9/SD10/SD14/SD15, SD1 Merrill, sd Quattro, DP Merrill, or dp Quattro body. Batch upload is supported — every file becomes a frame in the output slideshow.
2. Pick Merge strategy and Image Duration: Default is "Merge images" with 5 seconds per frame. Switch to "Video per image" if you want one ASF file per X3F. Adjust Duration (1/60 s to 10 s per frame) and set Background Color (default Black) for letterboxing when aspect ratios mismatch.
3. Set Resolution and Quality Preset (Optional): Keep original, choose a Fixed Resolution (480p, 720p, 1080p up to 4320p / 8K) or a Preset Resolution (1920x1080, 1280x720, social-media presets), or enter custom Width/Height with aspect lock. Under File Compression pick Constant Quality or Constraint Quality and a Preset (Lowest to Highest, default "Very High").
4. Convert and Download: Click "Convert." Files process in your browser session — no sign-up, no watermark, no Sigma Photo Pro install required.

Why Convert X3F to ASF?

X3F is Sigma's proprietary raw format that stores the layered red/green/blue data captured by the Foveon X3 sensor — color is sampled at every pixel location rather than reconstructed from a Bayer mosaic. ASF (Advanced Systems Format) is the Microsoft container that wraps Windows Media Video and Windows Media Audio streams. Converting a folder of X3Fs into a single ASF gives you a Windows-native slideshow video — useful when you need to drop a quick proof reel into PowerPoint, share frames with someone running a legacy Windows workflow, or archive a session in a format that plays back without a raw converter installed.

• Embed Sigma raws in a PowerPoint or Windows-native deck — PowerPoint accepts ASF/WMV without external codecs on Windows; an X3F-derived ASF plays inline where the raw itself cannot.
• Quick client review reel from a Sigma SD/DP shoot — turn 30-50 raws into a 2.5-4 minute auto-paced video instead of opening Sigma Photo Pro on the client's machine.
• Archive contact-sheet videos alongside the originals — a single ASF at 720p is dramatically smaller than the source X3F set (Merrill-era files run ~50 MB each) and still legible for thumbnail browsing.
• Hand off to a Windows-only collaborator — anyone with VLC, MPC-HC, or modern Windows builds can play ASF/WMV; no Sigma raw codec required.
• Generate a slideshow without desktop software — runs entirely in the browser, useful from a Chromebook or any machine without SPP installed.
• Re-encode legacy proofs into a single deliverable — if you already shoot Sigma, an ASF reel is the lowest-friction way to bundle frames for a Windows-centric stakeholder.

X3F vs ASF — Format Comparison

Output Settings Quick Guide

Frequently Asked Questions

Why convert X3F to ASF instead of MP4?

ASF is the right pick when the target environment is Windows-native and a single-file slideshow is the goal — PowerPoint on Windows embeds ASF/WMV without prompting for codecs, and Windows-era playback chains expect it. If you have no Windows-only constraint, MP4 with H.264 is more universally supported (browsers, mobile, macOS, smart TVs); consider X3F to MP4 instead. The Microsoft Learn docs themselves recommend the newer Source Reader / Sink Writer APIs over the legacy Windows Media Format SDK, which is a signal that ASF is in long-term maintenance mode.

How long will the output ASF be?

Output length equals frame count multiplied by Image Duration. Twenty X3Fs at the default 5 seconds = 100 seconds (~1 min 40 s). Drop Duration to 1 second for a fast contact-sheet reel or raise it to 10 seconds for a paced gallery. The actual rendered duration may shift fractionally if the encoder rounds to keyframe boundaries.

Will the Foveon color fidelity carry through?

Partially. The Foveon sensor's per-pixel R/G/B stack produces unusually clean color, but the X3F → ASF pipeline must demosaic (in this case, de-layer) into 8-bit RGB and then encode to WMV. You lose the raw headroom you'd keep in Sigma Photo Pro, and the lossy codec adds further compression. For colorimetric-grade output, develop the X3Fs in Sigma Photo Pro first and use the resulting TIFFs; ASF works best when the goal is playable presentation, not archival color.

Which Sigma cameras produce the X3F files I can upload?

Any X3F written by the Foveon X3 lineup: SD9, SD10, SD14, SD15, SD1, SD1 Merrill, sd Quattro, sd Quattro H, DP1/DP2/DP3, the DP Merrill series, and the dp Quattro series. Sigma discontinued the DP Quattro models in 2022 and has not shipped a new Foveon body since, but X3F files from earlier bodies remain valid input.

Can I add audio to the ASF?

This tool produces silent video from images. If you need narration or a music bed, generate the silent ASF here first, then mux audio in Shotcut, OpenShot, or any NLE that handles ASF/WMV. ASF natively carries WMA, AAC, AC-3, MP3, and other tracks — the container itself is codec-agnostic.

Why ASF instead of WMV?

They are effectively the same container — WMV is an ASF file whose primary stream is Windows Media Video. The .wmv extension is a hint to the OS that video is present; .asf is the more general label. If your downstream tool insists on .wmv, rename the file or use X3F to WMV directly.

Will the ASF play in modern browsers and on Mac?

ASF/WMV has no native browser support — Chrome, Firefox, Safari, and Edge will not play it inline without a plugin. On macOS, ASF requires VLC or a third-party codec pack; Apple has never bundled Windows Media playback. If you need universal playback, transcode the ASF to MP4 (H.264 + AAC) with ASF to MP4 after generation, or skip ASF entirely and use MP4 from the start.

How big can each X3F file be?

There is no per-file cap published for this tool; we have processed Merrill-era X3Fs (~50 MB each) and Quattro raws without issues. Processing happens in your browser session so the practical limit is your machine's available RAM — batches of 50-100 Merrill X3Fs may slow Chrome on machines with 8 GB or less. If you hit a wall, split the batch or downsample the X3Fs to TIFF first via X3F to TIFF.

Is there a faster alternative if I only want a contact sheet?

Yes — convert the X3Fs to JPG with X3F to JPG and arrange them in a contact-sheet PDF instead. The ASF route is for cases where playable video is specifically required (PowerPoint embed, Windows kiosk loop, legacy review workflow). For static review, JPG or TIFF will always be faster and smaller.