Image MIME Reference
Fuji-RAF
Fujifilm RAW Image
image/x-fuji-raf
VS
JPEG 2000 Image (HEIF Container)
image/hej2k
HEJ2K
A complete technical comparison of Fujifilm RAW Image and JPEG 2000 Image (HEIF Container) — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Fuji-RAF | HEJ2K |
|---|---|---|
| Transparency (Alpha) | ✕ No | Yes |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | Yes |
| EXIF Metadata | Yes | Yes |
| ICC Color Profile | Yes | Yes |
Fujifilm RAW Image
image/x-fuji-raf
Extension
.raf
Container
Proprietary RAF Container
Compression
Uncompressed / Lossless Compressed / Lossy Compressed (Modern firmware)
Algorithm
NoneProprietary LosslessProprietary Lossy
Color Depth
14-bit (Per Channel - X-Series), 16-bit (Per Channel - GFX Series)
Developed by
Fujifilm Corporation
Released
2000
Magic Bytes
46 55 4A 49 46 49 4C 4D 43 43 44 2D 52 41 57 20
JPEG 2000 Image (HEIF Container)
image/hej2k
Extension
.hej2
Container
HEIF / ISOBMFF (ISO/IEC 15444-16)
Compression
Lossy / Lossless
Algorithm
JPEG 2000HTJ2K
Color Depth
8-bit, 10-bit, 12-bit, 16-bit
Developed by
ISO/IEC JTC 1 / ITU-T
Released
2019
Magic Bytes
XX XX XX XX 66 74 79 70 6A 32 6B 69
Browser Support Comparison
| Browser | Fuji-RAF | HEJ2K |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Fuji-RAF
Fuji-RAF Strengths
- Retains absolute maximum sensor data, enabling massive shadow recovery and highlight protection compared to compressed in-camera JPEGs
- Stores proprietary Fujifilm Film Simulation metadata (like Classic Chrome or Acros), allowing editors to perfectly replicate in-camera aesthetics
- Very distinct and reliable magic header makes programmatic file detection foolproof
Limitations
- Proprietary format requires continuous updates to third-party software (like Lightroom) whenever Fujifilm releases a new camera
- The X-Trans sensor matrix requires highly specialized demosaicing algorithms that are extremely computationally expensive, leading to slower import and rendering times
- Completely unsupported in standard web browsers and basic operating system image viewers
HEJ2K
HEJ2K Strengths
- Brings the extensive capabilities of the HEIF container (like EXIF/XMP, thumbnails, and depth maps) to JPEG 2000
- Supports mathematically lossless compression via wavelet transformation
- High scalability and progressive decoding out of the box
Limitations
- Extremely limited software support outside of niche industries
- Zero native compatibility with web browsers
- High computational complexity compared to simpler formats like JPEG or PNG
When to choose which format
Fuji-RAF
Use Fuji-RAF when…
- Professional Digital Photography
- Fujifilm X-Trans Sensor Image Archival
- High Dynamic Range (HDR) Post-Processing
HEJ2K
Use HEJ2K when…
- Medical Imaging
- Geospatial Data
- Scientific Archiving