HDR to ARW Converter
Convert HDR to ARW in your browser. You download a Linear DNG (.dng), not a .arw: only a Sony camera can create a genuine ARW, and every editor that opens ARW 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 ARW
- 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 arw
Where a ARW would go
ARW files are opened by Sony Imaging Edge, Lightroom, Photoshop Camera Raw, Capture One and darktable, 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 ARW
What changes from HDR to ARW
Encoding: the HDR uses run-length encoded RGBE scanlines; ARW uses Sony's lossy compressed raw, uncompressed (since the A7R II) or lossless compressed (since the A1), 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; ARW allows 12 or 14 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; ARW 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; ARW can carry EXIF, Sony maker notes, a thumbnail and a full-size JPEG, 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 ARW
ARW is the raw format of Sony Alpha, RX and Cyber-shot cameras. It stores the sensor data (compressed, uncompressed or lossless compressed, depending on the model) with a full-size JPEG preview.
ARW is TIFF-based: the first directory carries EXIF and Sony's JPEG preview and the sensor data sits in a sub-directory. In Sony's classic compressed raw each block of 16 same-colour pixels keeps an 11-bit maximum and minimum plus 7-bit steps for the rest, which can leave artefacts beside high-contrast edges.
ARW files come from Sony Alpha mirrorless and SLT cameras, RX compacts and some Cyber-shot models.
When converting HDR to ARW makes sense
Forms and workflows that ask for ARW usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the ARW's place. Keep the HDR if you only need to view or share the picture.
What ARW offers when it comes straight from the camera: A full-size JPEG preview from the camera; Lossless compressed raw on recent bodies; Wide support across Sony's long Alpha line. Its drawbacks: Sony's classic compressed mode is lossy; Uncompressed files of 60 MB and more on high-resolution bodies; Creative Looks are ignored by most third-party raw editors.
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 .arw?
A real ARW is written by Sony cameras and holds the sensor's own readings (12 or 14 bits per channel, stored as Sony's lossy compressed raw, uncompressed (since the A7R II) or lossless compressed (since the A1)) along with EXIF, Sony maker notes, a thumbnail and a full-size JPEG. An HDR holds no sensor data, so no software outside the camera can create a genuine ARW. The Linear DNG you get instead is Adobe's open raw format, and every editor that opens ARW files opens it with the same raw controls. It holds decoded pixels, so it adds no quality or dynamic range.
Does converting HDR to ARW 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.