MOS to WebP Converter

Convert MOS to WebP Online

MOS is the Leaf Camera RAW format written by Leaf and Mamiya medium-format digital backs (the Leaf Aptus and Aptus-II series), and like all RAW files it holds the sensor's untouched data rather than a finished picture. This tool renders that RAW into a WebP — a small, web-ready image that opens directly in Chrome, Firefox, Edge, and Safari 16+ with no plugin. Because medium-format MOS captures are very high resolution (the 56 MP Aptus-II backs produce files around 78-115 MB), the resulting WebP can stay large and sharp while being a fraction of the size of the same image saved as JPEG or PNG.

How to Convert MOS to WebP

1. Upload Your MOS File: Drag and drop your .mos file onto the page, or click "+ Add Files" to browse. You can queue several MOS files and convert them in one batch.
2. Set the Quality Preset: Open Advanced Options and choose a Quality Preset (the default is "Very High"). Higher presets keep more detail and produce larger files; lower presets trade detail for a smaller WebP.
3. Choose Lossless or Resize (Optional): Flip "Lossless?" to "Yes" for a pixel-exact copy, or use the Resolution controls — Resolution Percentage, a preset size, or an exact Width x Height — to scale the high-resolution render down for the web.
4. Convert and Download: Click "Convert" and download your WebP. No sign-up, no watermark.

MOS RAW vs WebP — What Changes in the Conversion

A RAW render is one-way: the WebP is a developed image, so the exposure and white-balance latitude that lived in the MOS file is fixed once converted. Keep the original .mos if you may want to re-edit later. To preserve the full data instead, render to MOS to TIFF; for a universally compatible photo, use MOS to JPG.

Frequently Asked Questions

Will I lose editing latitude converting MOS to WebP?

Yes. MOS is RAW sensor data, so exposure, white balance, and highlight recovery are still adjustable in the original file. Rendering to WebP bakes those choices in, the same as exporting any RAW to a finished image. WebP itself is a high-quality target — Google measures lossy WebP at 25-34% smaller than equivalent JPEG and lossless WebP at 26% smaller than PNG — but the recoverable RAW data does not carry over. Keep the .mos if you might re-edit.

Should I pick lossy or lossless WebP for a MOS render?

Lossy (the default) gives the smallest file and is the right choice for sharing or the web. Choose Lossless (set "Lossless?" to "Yes") when you want a pixel-exact copy of the render — useful for archiving a high-resolution medium-format frame without generation loss. Lossless files are larger; for a 56 MP Aptus capture that can still be sizeable, but well below the original RAW.

Why is my converted WebP still a large file?

Leaf and Mamiya digital backs are medium-format, so a single MOS frame can be 40-80+ megapixels. The WebP keeps that full pixel dimension unless you resize, so a faithful render of a high-resolution capture is naturally a big image. To shrink it for the web, lower the Quality Preset or use the Resolution controls (Resolution Percentage or an exact Width x Height) to scale the render down.

Does WebP support transparency like the original capture might need?

WebP supports an alpha channel in both its lossy and lossless modes, so transparency is preserved if your image has it. A straight camera capture from a Leaf back has no transparency, but if you have processed the MOS into a layered or masked image elsewhere, the WebP output can hold the alpha. Per Google, lossless WebP adds transparency for about 22% more bytes.

What resolution will the WebP be, and can I control it?

By default the WebP matches the full pixel dimensions of the rendered MOS frame. In our testing, a Leaf Aptus-II 56 MP capture rendered at "Keep original" resolution stays at its native ~8,900-pixel-wide dimension, which is far larger than most screens need. Use Resolution Percentage to scale by a ratio, "Preset Resolutions" for common sizes, or "Width x Height" to set exact pixels — all keep aspect ratio unless you override both axes.

Are my MOS files kept private during conversion?

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — no sign-up, no watermark, never shared or made public. If you already have a WebP and only want to shrink it, compress WebP reduces the file without changing the format.