MOS Converter

How to Convert MOS to Any Format

1. Upload Your MOS File: Drag and drop your Leaf RAW file or click "Add Files". The converter reads .mos files from Leaf and Mamiya Leaf digital backs (Aptus, Aptus-II, AFi, Valeo, Credo). Batch is supported — drop in several MOS files and each one converts in parallel, then download them together as a ZIP.
2. Pick an Output Format and Quality Preset: Choose the target from the Image File Extension dropdown — JPG, PNG, TIFF, WEBP, PDF, BMP, GIF, HEIC, AVIF, and more. The default Quality Preset is "Very High (Recommended)"; lower it to shrink the file, or switch to Specific file size to cap the output at an exact MB target.
3. Set Conversion Quality, Resolution, or Bit Depth (Optional): For print-bound TIFF or PDF output, raise Conversion Quality (DPI) from the 300 DPI default up to 600 or 1200 DPI. Under Image resolution, keep original or scale down with Preset Resolutions or Resolution Percentage. For TIFF and PNG you can also toggle Lossless and choose a higher Bit Depth to preserve the digital back's wide tonal range.
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.

Popular MOS Conversions

• MOS to JPG — share or proof medium-format shots in the universal photo format
• MOS to PNG — lossless output for retouching and graphics work
• MOS to TIFF — a 16-bit archival master that editors open without a RAW plugin
• MOS to PDF — bundle contact sheets or proofs into one document
• MOS to WEBP — small, modern web delivery for portfolios
• MOS to BMP — uncompressed bitmap for legacy software
• MOS to GIF — quick low-color previews and thumbnails

Why Convert a MOS File?

MOS is the RAW image format written by Leaf and Mamiya Leaf medium-format digital backs — the Aptus, Aptus-II, AFi, Valeo, and Credo lines. Leaf shipped the first commercial medium-format digital back, the DCB1, back in 1991; the company passed through Scitex, then Kodak's Creo division, and is now part of Phase One, which also owns Mamiya. A MOS file is a TIFF-based wrapper holding the sensor's untouched RAW capture, often at 16 bits per channel, and it can be stored uncompressed or with lossless-JPEG compression on the back itself.

That richness is exactly why MOS is awkward to use directly. RAW formats are not finished images — they are sensor data that needs demosaicing and tone mapping before anything can display them, and almost no operating system, browser, email client, or web platform shows a .mos thumbnail. A common, well-documented snag: Adobe Camera Raw can open uncompressed MOS files but historically chokes on the compressed variant, which sends photographers hunting for Capture One or a converter just to see their own shots. Reasons people convert MOS:

• Share and proof (JPG / WEBP) — Clients, art directors, and web galleries want a flat, viewable image, not a RAW file. Converting MOS to JPG or WEBP produces something every device and browser opens instantly, at a fraction of the size.
• Edit without a RAW plugin (TIFF / PNG) — A 16-bit TIFF or a PNG is a flat, fully-rendered image that Photoshop, Affinity Photo, GIMP, and older software open with no camera-specific RAW support. TIFF keeps the wide tonal range for serious retouching; PNG is the lossless choice for compositing and graphics.
• Archive a viewable master (TIFF) — A 16-bit TIFF at 300–600 DPI is a stable, well-supported archival copy that will still open decades from now without depending on a discontinued RAW decoder.
• Deliver documents (PDF) — Turning proofs or selects into a PDF makes a single, paginated file you can email or print as a contact sheet.
• Legacy and web targets (BMP / GIF) — Some older kiosk and catalog software wants an uncompressed BMP; GIF is handy for tiny low-color previews and thumbnails.

MOS vs. Common Output Formats

Frequently Asked Questions

What is a MOS file and what camera makes it?

A MOS file is the RAW image format produced by Leaf and Mamiya Leaf medium-format digital camera backs — the Aptus, Aptus-II, AFi, Valeo, and Credo series. It is a TIFF-based container that stores the sensor's untouched capture, typically at 16 bits per channel, so it holds far more tonal and highlight detail than a finished JPEG. Because it is RAW sensor data rather than a rendered picture, you generally convert it to JPG, TIFF, or PNG before viewing, sharing, or editing it in everyday software.

Why won't my MOS file open in Photoshop or Camera Raw?

This is a long-standing, well-documented issue with Leaf files: Adobe Camera Raw can open uncompressed MOS files but historically does not read the compressed (lossless-JPEG) variant that many Leaf and Mamiya Leaf backs write by default. The usual fixes are to reshoot or re-export uncompressed from the back, or to process the file in Phase One Capture One or Leaf Capture first. The simplest path if you just need a usable image is to convert the MOS here to TIFF or JPG, which produces a flat, fully-rendered file that opens in any editor without a RAW plugin.

Will I lose image quality converting MOS to JPG?

Some, yes — JPG is an 8-bit lossy format, so it cannot carry the full 16-bit tonal range or the editing latitude of the RAW capture. For sharing, proofing, and web use the difference is invisible, and keeping the Quality Preset at "Very High" preserves plenty of detail. If you want to keep the headroom for later editing, convert to a 16-bit TIFF or PNG instead, and treat the JPG as a delivery copy rather than a master.

What output format keeps the most quality from a MOS file?

A 16-bit TIFF. TIFF is lossless and supports 16 bits per channel, so it preserves the wide dynamic range and smooth gradients a medium-format back captures — making it the best archival or editing master. PNG is also lossless and a good choice for graphics and compositing, though 16-bit PNG support is less universal across older software. JPG and WEBP are smaller and more shareable but discard tonal data, so use them for delivery rather than as your working file.

Does converting set the exposure and white balance, or do I lose RAW control?

Conversion renders the MOS to a finished image using a standard demosaic and the capture's embedded settings — it is not a full RAW-editing session. If you need to push exposure, recover highlights, or set a custom white balance from the RAW data, do that in a dedicated RAW processor such as Capture One first, export, and use this converter for the final format change. For a straightforward "make it viewable and shareable" job, a direct MOS-to-JPG or MOS-to-TIFF conversion is all you need.

Can I convert several MOS files at once?

Yes. Drop multiple .mos files into the uploader and each one converts in parallel using the same output settings, which is handy for processing a full shoot or a folder of selects. When the batch finishes you can download every result together as a single ZIP. In our testing, a batch of medium-format MOS files converted to JPG at "Very High" quality completes well within the time it takes to upload them — the upload, not the conversion, is the slow part for these large RAW files.

Are my MOS files kept private?

Yes. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — there is no sign-up, no watermark, and your files are never shared or made public. The practical limit on a large MOS file is upload time, not a fixed size cap; uncompressed medium-format RAW files can be hundreds of megabytes, so a faster connection helps most.