Image MIME Reference
Panasonic-RAW-(RW2)
Panasonic RAW Image
image/x-panasonic-raw
VS
Sony SR2 Raw Image
image/x-sony-sr2
Sony-SR2
A complete technical comparison of Panasonic RAW Image and Sony SR2 Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Panasonic-RAW-(RW2) | Sony-SR2 |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
Panasonic RAW Image
image/x-panasonic-raw
Extension
.raw.rw2
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Panasonic Proprietary Lossless
Algorithm
NoneProprietary Lossless
Color Depth
12-bit (Per Channel), 14-bit (Per Channel), 16-bit (Per Channel - High-res mode)
Developed by
Panasonic Corporation
Released
2004
Magic Bytes
Older RAW: 49 49 2A 00 | Newer RW2: 49 49 55 00
Sony SR2 Raw Image
image/x-sony-sr2
Extension
.sr2
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Sony Proprietary Lossless
Algorithm
NoneSony Proprietary Lossless
Color Depth
12-bit (Per Channel)
Developed by
Sony Corporation
Released
2005
Magic Bytes
49 49 2A 00
Browser Support Comparison
| Browser | Panasonic-RAW-(RW2) | Sony-SR2 |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Panasonic-RAW-(RW2)
Panasonic-RAW-(RW2) Strengths
- Retains maximum sensor data, allowing significant recovery of highlights and shadows compared to in-camera JPEGs
- Modern RW2 files embed proprietary lens correction profiles (distortion, vignetting, chromatic aberration) that raw converters can automatically apply
- The unique 'IIU' signature on RW2 files makes programmatic identification extremely reliable compared to other TIFF-spoofing raw formats
Limitations
- Proprietary format requires continuous updates to third-party processing engines whenever Panasonic releases a new Lumix camera
- Produces very large file sizes, particularly when using Panasonic's High-Resolution multi-shot modes
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
Sony-SR2
Sony-SR2 Strengths
- Retains raw, unprocessed sensor data from legacy cameras, allowing modern raw processors to extract vastly superior image quality than what was possible in 2005
- Utilizes a standard TIFF container structure, ensuring that community-maintained open-source decoding libraries (like LibRaw) can easily parse and maintain support for it indefinitely
Limitations
- Completely obsolete format that has not been utilized in a new camera release in over a decade
- MIME detection via magic bytes is unreliable due to TIFF header spoofing, requiring deeper EXIF inspection
- Cannot be natively viewed in web browsers or standard operating system image viewers without specialized decoders
When to choose which format
Panasonic-RAW-(RW2)
Use Panasonic-RAW-(RW2) when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Lumix Archival
Sony-SR2
Use Sony-SR2 when…
- Legacy Sony Cyber-shot/Alpha Photography
- Non-destructive Image Post-Processing
- Raw Imaging Archival