MOS to HEIC Converter

MOS to HEIC Converter

A .mos file is the raw capture from a Leaf or Mamiya medium-format digital back — a large, sensor-level negative meant for editing in Capture One or Camera Raw, not for sharing. HEIC is Apple's compact still-image format: an HEVC-encoded picture in an HEIF container that holds roughly the same quality as JPEG in about half the bytes. Converting MOS to HEIC renders the raw into a finished, much smaller image. Two things are worth knowing before you do it: rendering bakes in white balance and exposure, so you lose the editing latitude the raw gave you, and HEIC is largely an Apple-ecosystem format — for an image that opens anywhere, convert MOS to JPG instead.

MOS Format at a Glance

HEIC Format at a Glance

How to Convert MOS to HEIC

1. Upload Your MOS File: Drag and drop your .mos file or click "Add Files" to select it. You can queue several backs' captures and convert them together.
2. Pick a Quality Preset: Choose a preset from "Very High (Recommended)" down to lower settings — higher quality keeps more detail and HDR range, lower settings shrink the file. Or switch to "Specific file size" to target an exact size.
3. Set Resolution (Optional): Keep the original dimensions, scale by a "Resolution Percentage," or pick a preset / custom width and height with aspect ratio locked — useful for taming the very large pixel count of a medium-format back.
4. Convert and Download: Click Convert and save your HEIC. No sign-up, no watermark.

Frequently Asked Questions

Will I lose image quality converting MOS to HEIC?

Two separate things happen. First, the raw is rendered to a finished image, which bakes in white balance, exposure, and tone — you give up the editing latitude the .mos held, so keep the original if you may re-edit. Second, HEIC itself is lossy, though at the "Very High" preset the visible loss is minimal and HEIC preserves detail better than JPEG at the same file size.

Why is my HEIC so much smaller than the MOS it came from?

A medium-format .mos stores high-bit-depth data for every sensor photosite, often as uncompressed or lossless-compressed raw, so files run very large. HEIC stores a rendered, lossy, HEVC-encoded picture that is roughly half the size of an equivalent JPEG. The combined effect is a dramatic size drop — that is the point of the conversion, but it is one-way.

Can HEIC keep the 10-bit color and HDR from a medium-format capture?

HEIC supports 10-bit and 12-bit encoding, so it can carry far more tonal range than 8-bit JPEG and is capable of HDR. It cannot match the full linear bit depth of the original raw, but choosing a high quality preset preserves the widest tonal range HEIC allows.

Will the HEIC open on Windows or Android?

Not always out of the box. HEIC is native on Apple devices (iOS 11+ and macOS High Sierra+, both from 2017). Windows can open it once the HEVC/HEIF codec support is installed, and Android 10 and later generally support it, but browser support is inconsistent. For a file that opens reliably everywhere, convert MOS to JPG instead, or run the HEIC through our HEIC to JPG converter afterward.

Does the converter need Capture One or Leaf software installed?

No. The conversion runs on our servers, so you do not need Capture One, Leaf Capture, or any raw processor on your own machine. In our testing the renderer reads both the uncompressed and lossless-JPEG-compressed MOS variants; very old or unusually packaged Leaf files occasionally fail to decode, in which case exporting a TIFF from Capture One first and converting that is the reliable fallback.

What happens to my MOS file after I convert it?

Your file is uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion. There is no sign-up, no watermark, and files are never shared or made public.