Image MIME Reference
Canon-CR2
Canon Raw Version 2
image/x-canon-cr2
VS
JPEG 2000 Image (HEIF Container)
image/hej2k
HEJ2K
A complete technical comparison of Canon Raw Version 2 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 | Canon-CR2 | 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 |
Canon Raw Version 2
image/x-canon-cr2
Extension
.cr2
Container
TIFF
Compression
Lossless JPEG (ITU-T81)
Algorithm
Lossless JPEG (ITU-T81)
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Canon Inc.
Released
2004
Magic Bytes
49 49 2A 00 10 00 00 00 43 52 02 00
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 | Canon-CR2 | HEJ2K |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Canon-CR2
Canon-CR2 Strengths
- Retains maximum sensor data, allowing extreme recovery of highlights and shadows that would be permanently lost in a JPEG
- White balance and color profiling are not 'baked in', meaning they can be completely altered in post-production without degrading the image
- Lossless compression ensures perfect pixel accuracy while reducing file size compared to fully uncompressed formats
Limitations
- Proprietary format means it requires constant updates to raw processing engines (like Adobe Camera Raw) every time Canon releases a new camera model
- Produces very large file sizes (often 20MB to 40MB per image depending on sensor resolution)
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
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
Canon-CR2
Use Canon-CR2 when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival
HEJ2K
Use HEJ2K when…
- Medical Imaging
- Geospatial Data
- Scientific Archiving