Convert MEF to BMP — Free Online Converter
Convert Mamiya Raw Format (.mef) to Bitmap Image (.bmp) online for free. Fast, secure image conversion with no watermarks or registration....
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Upload your .mef file by dragging it into the upload area or clicking to browse.
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About MEF to BMP Conversion
MEF is the proprietary RAW image format produced by Mamiya medium format cameras, including the 645AFD, 645DF, 645DF+, and cameras equipped with Phase One digital backs such as the P-series and IQ-series. These cameras capture extraordinarily high-resolution images from medium format CCD and CMOS sensors ranging from 22 to 80+ megapixels, producing MEF files that contain the full unprocessed sensor data at 14-16 bit depth.
Converting MEF to BMP produces an uncompressed Windows bitmap where every demosaiced pixel is stored as raw RGB data. BMP's straightforward structure ensures universal readability by any application, but the uncompressed nature means extremely large output files — a 60-megapixel Mamiya/Phase One capture produces a BMP exceeding 170 MB. This conversion serves specialized workflows requiring uncompressed pixel data from medium format studio captures.
Why Convert MEF to BMP?
Mamiya medium format cameras are used extensively in high-end commercial photography, fine art reproduction, and scientific imaging. The MEF format, while supported by Capture One and some versions of Lightroom, is not compatible with many industrial, scientific, and legacy systems that require uncompressed BMP input. Machine vision, archival scanning quality control, and museum imaging systems often mandate BMP format.
The extraordinary resolution of Mamiya medium format sensors (up to 80+ megapixels with Phase One backs) produces images suitable for billboard-sized prints and extreme detail work. Converting to BMP ensures this high-resolution data is accessible in uncompressed form for systems that cannot decode modern RAW or compressed formats.
Common Use Cases
- Supply Mamiya 645DF+ studio photographs to museum archival systems requiring uncompressed BMP input
- Feed Phase One IQ-series captures into scientific imaging analysis pipelines
- Deliver Mamiya medium format photographs to industrial quality control systems that mandate BMP
- Create uncompressed reference copies of high-resolution medium format captures for pixel-level inspection
- Prepare MEF files from fine art reproduction shoots for legacy archival management systems
How It Works
The conversion reads the MEF file's TIFF-based container structure, extracts the 14-16 bit Bayer pattern data from the medium format sensor, and performs demosaicing to produce full RGB pixels. Mamiya and Phase One camera metadata — including white balance coefficients, color matrix, black level calibration, and lens correction data — is applied during processing. The resulting image is written as a 24-bit Windows BMP. A 60 MP Phase One IQ260 capture produces a BMP of approximately 172 MB, while a 22 MP Mamiya 645AFD produces about 63 MB.
Quality & Performance
BMP applies zero compression, so no artifacts are introduced during the format conversion. The output is a faithful representation of the demosaiced medium format sensor data at 8 bits per channel. The 14-16 bit RAW depth is truncated to 8-bit BMP, losing the deep shadow and highlight recovery capability of the original MEF file. For the absolute highest quality output from medium format captures, TIFF at 16 bits per channel is a better choice.
Device Compatibility
| Device | MEF | BMP |
|---|---|---|
| Windows PC | Partial | Native |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No | No |
Tips for Best Results
- 1BMP files from medium format sensors are enormous — a 60 MP capture produces a 172 MB BMP
- 2Use TIFF with 16-bit depth instead of 8-bit BMP to preserve the full quality of the medium format sensor
- 3For general use, convert to PNG or JPEG rather than BMP — BMP is only for systems requiring uncompressed input
- 4Batch converting large MEF collections to BMP requires significant disk space — plan carefully
- 5Keep original MEF files as archival masters — they contain far more data than any 8-bit output format
MEF to BMP conversion serves specialized workflows requiring uncompressed pixel data from Mamiya medium format cameras. The files are very large due to the high sensor resolution, but universally compatible.