MEF File

What are MEF files and how to open them

Are you having problems opening a MEF file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your MEF files.

What is a MEF file?

MEF files have multiple uses, and CA Visual Objects Module Export is one of them. Read more about the other uses further down the page.

CA Visual Objects Module Export File

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open MEF files

Important: Different programs may use files with the MEF file extension for different purposes, so unless you are sure which format your MEF file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different MEF openers which you will find listed below.

Last updated: January 22, 2025

All known file formats using extension .MEF

While CA Visual Objects Module Export File is a popular type of MEF-file, we know of 4 different uses of the .MEF file extension. Different software may use files with the same extension for different types of data.

Camera RAW Image File (Mamiya)

Camera RAW Image File (Mamiya) with the .MEF extension is a raw photo file created by certain Mamiya digital cameras, especially the Mamiya ZD line. It stores unprocessed sensor data exactly as the camera captured it without adjustments for color, exposure, or sharpening. This lets photographers have full control when editing the image on a computer.

A Mamiya camera writes the .MEF file to its memory card when set to shoot in RAW or RAW+JPEG mode. These files include embedded metadata such as exposure settings, white balance, lens identification, and camera model. After transferring to a computer, they must typically be developed or converted into more common image formats (such as TIFF or JPEG) using specialized software that supports Mamiya's MEF format.

The MEF format uses a TIFF-based file structure, with big-endian byte order and a signature starting at the file's beginning of 4D 4D 00 2A (in hexadecimal). It supports high bit depths (often 12- or 14-bit), lossless compression, and uses the RGB color space with metadata stored using EXIF conventions.

MEF opener for Windows

We have identified 3 MEF openers that are compatible with this specific type of MEF file.

MAIET Encrypted File System

We know that one MEF format is MAIET Encrypted File System. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Mirror II Emulation File

We know that one MEF format is Mirror II Emulation File. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of MEF files. Remember, different programs may use MEF files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about MEF file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.