Image MIME Reference
FST-Image
FAST Search & Transfer Image
image/vnd.fst
VS
Sony Alpha Raw Image
image/x-sony-arw
Sony-ARW
A complete technical comparison of FAST Search & Transfer Image and Sony Alpha Raw Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | FST-Image | Sony-ARW |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | Yes |
| ICC Color Profile | ✕ No | Yes |
FAST Search & Transfer Image
image/vnd.fst
Extension
.fst
Container
Proprietary FAST Container
Compression
Proprietary
Algorithm
Unknown (Proprietary FAST encoding)
Color Depth
Unknown
Developed by
FAST Search & Transfer ASA (Arild Fuldseth)
Released
2000
Magic Bytes
Unknown (Proprietary)
Sony Alpha Raw Image
image/x-sony-arw
Extension
.arw
Container
TIFF-based (Proprietary)
Compression
Uncompressed / Lossless Compressed / Lossy Compressed
Algorithm
NoneSony Proprietary LosslessSony Proprietary Lossy
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Sony Corporation
Released
2006
Magic Bytes
49 49 2A 00
Browser Support Comparison
| Browser | FST-Image | Sony-ARW |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
FST-Image
FST-Image Strengths
- Historically served as an optimized, compressed format for FAST's early multimedia and live streaming engines over constrained late-1990s bandwidth
Limitations
- Completely obsolete and non-functional in modern software ecosystems
- Undocumented, closed-source binary structure with zero support in modern image processing libraries
- Shares its file extension with several other distinct file types (such as FL Studio state files or FAST Search dictionaries), leading to easy misidentification
Sony-ARW
Sony-ARW Strengths
- Retains absolute maximum sensor data, enabling massive shadow recovery and highlight protection compared to compressed in-camera JPEGs
- Embeds high-quality JPEG previews and robust metadata, allowing photographers to match in-camera color science (like Creative Looks) perfectly during raw processing
- Utilizes the standard TIFF container structure, ensuring broad compatibility with open-source decoding libraries (like LibRaw)
Limitations
- Proprietary format means it requires constant updates to raw processing engines every time Sony releases a new camera model
- Sony's historically controversial lossy compression algorithm (often called 'star eater' due to spatial filtering artifacts) was a drawback for astrophotography in older ARW versions, though largely resolved in newer models with uncompressed/lossless options
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
When to choose which format
FST-Image
Use FST-Image when…
- Historical FAST Enterprise Search Indexing
- Legacy Proprietary Multimedia Streaming (late 1990s)
- Internal Media Transmission
Sony-ARW
Use Sony-ARW when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival