HDR to ORF Converter
Convert HDR to ORF in your browser. You download a Linear DNG (.dng), not a .orf: only an Olympus camera can create a genuine ORF, and every editor that opens ORF also opens DNG. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
HDR expected · other image formats also work
How to use HDR to ORF
- 1
Add your HDR files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the DNG 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 .dng files one at a time or together as a ZIP.
Why use Aback Images for hdr to orf
Where a ORF would go
ORF files are opened by OM Workspace, Lightroom, Photoshop Camera Raw, Capture One and RawTherapee, and every one of them opens the DNG too.
DNG next to HDR
The DNG is written uncompressed, so expect it to be several times larger than the HDR, which stores run-length encoded RGBE scanlines.
Written without a lossy pass
The DNG is written uncompressed, so the pixels decoded from the HDR arrive unchanged, apart from precision beyond 8 bits per channel.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
HDR vs ORF
What changes from HDR to ORF
Encoding: the HDR uses run-length encoded RGBE scanlines; ORF uses losslessly compressed sensor data, with a preview and thumbnail, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.
Bit depth: an 8-bit mantissa per channel sharing an 8-bit exponent (RGBE), 32 bits per pixel in the HDR; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
Colour: linear RGB (or XYZ in the XYZE variant) in the HDR; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.
Metadata: the HDR can carry a text header with FORMAT, EXPOSURE and optional comments; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.
About HDR
Radiance .hdr stores high dynamic range light values, widely used for 3D environment maps and HDRI lighting.
A Radiance file starts with '#?RADIANCE' (or '#?RGBE'), text lines such as FORMAT=32-bit_rle_rgbe and EXPOSURE, a blank line, a resolution line like '-Y 2048 +X 4096', then the scanlines.
HDR files usually come from HDRI environment maps, 360° panoramas and lighting simulation.
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 come from Olympus E-series DSLRs, OM-D and PEN mirrorless cameras and OM System bodies.
When converting HDR to ORF makes sense
Forms and workflows that ask for ORF usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the ORF's place. Keep the HDR if you only need to view or share the picture.
What ORF offers when it comes straight from the camera: Compact files from a smaller Four Thirds sensor; High Res Shot results stored as a single file; Supported across two decades of Olympus and OM System bodies. Its drawbacks: An 'IIRO' header that generic TIFF readers reject; 12-bit depth, less than most full-frame raw files; A preview hidden inside the maker notes.
Limitations
- Light values above 1.0 are clipped rather than tone-mapped, so the sun and bright sky turn flat white.
- Environment maps are 2:1 equirectangular panoramas, so the picture looks stretched near the top and bottom, as it should.
- Files in the XYZE variant cannot be read here; RGBE files, the common kind, can.
- The DNG holds the decoded 8-bit pixels, so it adds no dynamic range or detail beyond the HDR.
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Frequently asked questions
Why do I get a .dng file instead of a .orf?
A real ORF is written by Olympus cameras and holds the sensor's own readings (12 bits per channel, stored as losslessly compressed sensor data, with a preview and thumbnail) along with EXIF and Olympus maker notes, which also contain the preview. An HDR holds no sensor data, so no software outside the camera can create a genuine ORF. The Linear DNG you get instead is Adobe's open raw format, and every editor that opens ORF files opens it with the same raw controls. It holds decoded pixels, so it adds no quality or dynamic range.
Does converting HDR to ORF lose quality?
DNG is written uncompressed, so the pixels are stored exactly as decoded. The high dynamic range is mapped to 8 bits per channel, and values above white clip.
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.