MOS to PNG Converter

Convert MOS to PNG Online

MOS is the raw capture format from Leaf and Mamiya medium-format digital backs (the Leaf Aptus and Aptus-II line), normally opened only in Capture One or Leaf Capture. This converter renders that raw sensor data into a standard PNG so the shot opens in any image viewer, browser, or editor — while keeping the most quality a non-raw export can hold, since PNG is fully lossless. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark.

How to Convert MOS to PNG

1. Upload Your MOS File: Drag and drop your .mos file or click "+ Add Files". Batch upload is supported, so a whole shoot can be converted in one pass.
2. Set Image Resolution (Optional): Leave it at ORIGINAL to keep the full medium-format pixel dimensions, or use Preset Resolutions / Width x Height to downscale a large file for web or proofing.
3. Choose Bit Depth and Colors (Optional): Keep the default 8-bit RGB for a universally compatible file, or use the bit-depth and Colors controls if you need a deeper or palette-reduced PNG. PNG stays lossless either way.
4. Convert and Download: Click "Convert" and download the PNG. No sign-up, no watermark.

MOS RAW vs the PNG You Get

A raw .mos file stores the unprocessed sensor reading plus full editing latitude; rendering it to PNG bakes in the white balance, exposure, and tone, trading that latitude for a finished, universally readable image.

Frequently Asked Questions

Will I lose image quality converting MOS to PNG?

The pixels are not re-compressed lossily — PNG uses DEFLATE, a lossless algorithm, so the rendered image is stored bit-for-bit. What you lose is raw latitude: once the .mos is rendered, exposure, white balance, and highlight recovery are baked in and can no longer be pushed the way Capture One can push the raw file. For a finished image meant to be viewed or shared, PNG is the highest-quality non-raw export; for ongoing editing, keep the original MOS.

How big will the output PNG be?

Medium-format Leaf and Mamiya backs run from roughly 22 to 80 megapixels, so a full-resolution lossless PNG can be tens of megabytes — larger than the equivalent JPEG because nothing is thrown away. If you only need a proof or web image, downscale with Preset Resolutions or Width x Height in step 2 to bring the size down. Want a smaller, lossy file instead? Use MOS to JPG.

Should I export 8-bit or 16-bit PNG?

PNG supports 1, 2, 4, 8, and 16 bits per channel. 8-bit (the default) is universally compatible and fine for screen use and sharing. 16-bit preserves more tonal gradation from the medium-format raw, which matters if you intend to do further grading on the PNG — but it roughly doubles file size and not every older viewer handles 16-bit PNG. When in doubt, 8-bit is the safer default.

Does the PNG keep CMYK or a print color profile?

No. PNG is an RGB-only format and has no CMYK mode, so a press-bound conversion will be converted to RGB. If you need CMYK or to retain maximum editing headroom and embedded profiles for print, render to TIFF instead with MOS to TIFF, which supports higher bit depths and richer metadata than PNG.

Why can't my normal photo app open the MOS file in the first place?

MOS is a proprietary raw format tied to Leaf and Mamiya digital backs and is only natively decoded by Capture One, Leaf Capture, and certain Adobe Camera Raw builds. General-purpose viewers and browsers do not ship a MOS decoder, which is exactly why converting to PNG is useful — the output opens anywhere with no special software.

Is anything kept on your servers after I convert?

In our testing the workflow is upload, server-side render, download: the file is sent over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion. No account, no watermark, and your image is never shared or made public.