Mamiya MEF to JPG

MEF is the proprietary raw format used by Mamiya digital medium format cameras and backs. It holds unprocessed sensor data, which gives great editing flexibility but large files that standard viewers, browsers and social platforms cannot open. Converting to JPG lets you share proofs with clients, post to your portfolio or preview a shoot without raw software. This tool uses the JPEG preview stored inside each MEF file.

It runs entirely in your web browser. Drag your MEF files onto the drop area or click to choose them, set the JPG Quality slider, and click Convert Files. For each file the tool finds the largest JPEG preview the camera embedded, rotates it according to the file's orientation and saves it as a JPG at your chosen quality. Each JPG downloads automatically as soon as it is done.

Raw editors are ideal for retouching and color grading, but loading large medium format files into a full editing suite just to send a reference image takes time. This converter is a lightweight shortcut: it gives you JPGs of the camera's own rendering in seconds, without touching your catalog. Use it for quick proofs, reviews on a device without raw support, or a fast look at a folder.

Right after a shoot, to send quick proofs or contact sheets before you commit to retouching. It is also handy when archiving older Mamiya projects, to create a lightweight visual index of your folders, or when you need to share a behind-the-scenes preview while still on location. For final deliveries, export from your edited raw files instead, since this tool uses the camera's preview.

Two reasons. MEF files store the full sensor data at high bit depth, while a JPG uses lossy compression designed to keep files small. And the JPG is made from the preview the camera embedded, which on some models is smaller than the full sensor resolution, so it can have fewer pixels as well. The result is a manageable, universally compatible file for viewing and sharing.

RAW+JPEG gives you both files straight away, but uses more card space on every frame, which adds up with medium format files. Shooting raw only and converting later saves that space, and you convert just the frames you need. The JPG this tool produces is the preview the camera already stored in the raw file, so it reflects the camera's own rendering rather than a full-size in-camera JPEG.

No. The tool only reads your MEF files and never changes, overwrites or deletes them. Each JPG is a new, separate file created in your browser and saved to your downloads, while your originals keep all their sensor data for future editing. The JPGs are lightweight copies for sharing and display; your masters stay untouched in your archive.

Yes. Select a group of MEF files or drag them onto the drop area together, and add more whenever you like. When you click Convert Files, the tool processes them one after another and downloads each JPG as it finishes, skipping any already done. Allow multiple downloads if your browser asks. Click Clear List to start a new batch.

If a file shows No preview image found, it holds no JPEG preview the browser can decode, and the tool cannot develop the raw sensor data instead. If the preview could not be decoded, the file may be incomplete, for example after an interrupted card transfer, so copy it again from the card or backup. Check that it is a genuine .mef file, and try an up-to-date browser.

The JPG shows the colors the camera rendered for its preview, using the white balance and settings at the time of capture, at 8 bits per channel. That is a faithful proof of what you shot, but it will not match a hand-edited raw file, and it has none of the highlight recovery or shadow detail a raw processor can draw out. For final color, develop the MEF in your raw editor.