HEIC to ORF Converter
Convert HEIC 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
HEIC expected · other image formats also work
How to use HEIC to ORF
- 1
Add your HEIC files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since DNG has none.
- 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 heic 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 HEIC
The DNG is written uncompressed, so expect it to be several times larger than the HEIC, which stores lossy HEVC (H.265) intra coding, on iPhones as a grid of 512×512 tiles.
No new artefacts
HEIC is already lossy, since it stores lossy HEVC (H.265) intra coding, on iPhones as a grid of 512×512 tiles; the DNG keeps the 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.
HEIC vs ORF
What changes from HEIC to ORF
Encoding: the HEIC uses lossy HEVC (H.265) intra coding, on iPhones as a grid of 512×512 tiles; 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: 8 or 10 bits per channel in the HEIC; ORF allows 12 bits per channel, and the DNG written here has 8 bits per channel, linearised. 10-bit HEIC photos are reduced to 8 bits per channel.
Colour: YCbCr, usually tagged Display P3 on iPhones in the HEIC; ORF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.
Transparency: the HEIC stores it as an auxiliary image item, rarely used by cameras; the DNG has none, so transparent areas are filled with the colour you choose.
Other images: the HEIC can hold a thumbnail, depth map, HDR gain map and burst shots as extra items; only the main image is converted.
Metadata: the HEIC can carry EXIF, XMP and an ICC profile, stored as items; ORF can carry EXIF and Olympus maker notes, which also contain the preview, but nothing is copied across.
About HEIC
HEIC is the default photo format on iPhones and many Android phones. It is about half the size of JPEG, but Windows, many websites and older software cannot open it without converting.
A HEIC is a HEIF file (ISO base media boxes with the brand 'heic'). iPhone photos store the picture as a grid of 512×512 HEVC tiles that the decoder stitches together, with the thumbnail, depth map and HDR gain map as further items.
HEIC files usually come from iPhones and iPads since iOS 11, and many recent Android phones.
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 HEIC 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 HEIC 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
- iPhone photos are usually Display P3; colours are mapped to sRGB, so very saturated reds and greens can look slightly less vivid.
- The DNG holds the decoded 8-bit pixels, so it adds no dynamic range or detail beyond the HEIC.
More conversions
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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. A HEIC 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 HEIC to ORF lose quality?
DNG is written uncompressed, so the pixels are stored exactly as decoded. Artefacts already in the HEIC stay, but nothing new is lost. 10-bit HEIC photos are reduced to 8 bits per channel. Not carried over: any a thumbnail.
What happens to transparency when converting HEIC to ORF?
HEIC stores transparency as an auxiliary image item, rarely used by cameras. DNG has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
Why can't I open HEIC photos on Windows or websites?
HEIC uses the HEVC codec, which is patent-encumbered and not built into most browsers, Windows apps and upload forms. Converting makes the photo open where HEIC does not, and the HEIC is decoded inside your browser to do it.
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.