All about ARW files
ARW stands for Alpha RAW and is the file format for raw data from Sony Alpha cameras, introduced in 2006. The first camera to use this format was the DSLR-A100.
Technically, all ARW files are based on the TIFF structure and contain, in addition to the raw image data, an embedded low-resolution JPEG preview image. Furthermore, extensive metadata relating to camera settings, exposure settings and white balance is included.
Versions and development
There are currently five versions of ARW files; see the table below:
| Version | Year | Main change |
|---|---|---|
| ARW 1.0 | 2006 | First version (DSLR-A100), 12-bit |
| ARW 2.1 | 2008 | Compressed RAW (cRAW), lossy |
| ARW 2.3 | 2012 | 14-bit colour depth (from SLT-A99 onwards) |
| ARW 4.0 | 2021 | Lossless compression (Sony A1) |
| ARW 5.0 | 2023 | Current version (A9 III, A1 II) |
Compression modes
For a long time, Sony offered only two compression options: lossy compression (cRAW) or uncompressed. cRAW compression uses a delta encoding method. Whilst this saves storage space, it can lead to visible artefacts, for example in high-contrast scenes. It was not until 2021 that Sony introduced lossless compression with the A1. There are therefore currently 3 compression modes:
Compressed: Lossy (cRAW) – but smallest file sizes
Lossless Compressed: Lossless compression (Lossless JPEG92)
Uncompressed: Maximum file size (but lossless)
Sources
Convert, open and edit ARW files
Details about ARW files
- Software for opening ARW files
- Software for editing ARW files
- MIME-type for ARW
No Comments