ORF to BMP Converter
Convert ORF to BMP in your browser. The preview inside the maker notes is found by scanning the whole file, and that preview is what gets converted. No raw development happens here. You get an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
RAW expected · other image formats also work
How to use ORF to BMP
- 1
Add your ORF files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the BMP is written uncompressed. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .bmp files one at a time or together as a ZIP.
Why use Aback Images for orf to bmp
Where the BMP goes next
BMP opens in every operating system and browser.
BMP next to ORF
The BMP stores the camera preview's pixels uncompressed, so it can be as large as the 12 to 30 MB raw file, or larger, depending on the preview's resolution.
No new artefacts
The preview inside the ORF is a camera JPEG; the BMP stores its decoded pixels uncompressed, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
ORF vs BMP
What changes from ORF to BMP
Encoding: the ORF uses losslessly compressed sensor data, with a preview and thumbnail; BMP uses usually none; RLE for some 4 and 8-bit files, and the download is an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency.
Bit depth: 12 bits per channel in the ORF; BMP allows 1, 4, 8, 16, 24 or 32 bits per pixel, and the BMP written here has 24 or 32 bits per pixel. The sensor's 12 bits are not used: the 8-bit camera preview is converted.
Colour: camera RGB from a Bayer mosaic in the ORF; BMP supports RGB or an indexed palette, written here as 8-bit sRGB.
Metadata: the ORF can carry EXIF and Olympus maker notes, which also contain the preview; BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers), but nothing is copied across.
About ORF
ORF is the raw format of Olympus and OM System cameras, built around Four Thirds and Micro Four Thirds sensors. It stores 12-bit sensor data with a JPEG preview kept inside Olympus's maker notes.
ORF looks like TIFF but replaces the version number 42 with the letters 'RO', so a little-endian file starts 'IIRO' and generic TIFF readers reject it. Its JPEG preview is not in the main image directory but inside the camera-settings block of Olympus's maker notes.
ORF files usually come from Olympus E-series DSLRs, OM-D and PEN mirrorless cameras and OM System bodies.
About BMP
BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.
A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.
When converting ORF to BMP makes sense
BMP is the better choice for legacy software and embedded systems that require it, while ORF suits editing Olympus and OM System photos in a raw developer.
BMP strengths: No compression artifacts; Read by very old and very simple software. Drawbacks to weigh: Enormous files; Poor support for transparency; No metadata.
Limitations
- High Res Shot files combine several exposures in camera; the preview shows the combined result at its stored size.
- A BMP is uncompressed, about 3 bytes per pixel, or 4 with transparency, so expect a large file.
- Some older programs ignore the alpha channel of a 32-bit BMP and show transparent areas as black or white.
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Frequently asked questions
Does converting ORF to BMP lose quality?
BMP is written uncompressed, so the pixels are stored exactly as decoded. Those pixels come from the camera's JPEG preview, so its compression stays, but nothing new is lost. The sensor's 12 bits are not used: the 8-bit camera preview is converted.
Which apps open BMP files?
Every operating system and browser.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.