Olympus Raw Format (.orf)
TIFF-based StandardOlympus Raw Format (ORF) is the proprietary RAW image format captured by Olympus and OM System Micro Four Thirds and Four Thirds digital cameras, known for computational High-Res Shot modes.
Convert ORF to JPG
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Inspect & Metadata
Operating systems and file analyzers identify ORF files by inspecting the leading binary byte sequence:
Byte-Level Header Signature (Magic Bytes)
Operating systems and file analyzers identify ORF files by inspecting the leading binary byte sequence:
HEX SIGNATURE (OFFSET 0):
49 49 52 4FASCII REPRESENTATION: IIRO
Standardization: TIFF-based proprietary format
Technical Specifications
| Container Architecture | TIFF-based container with signature 'IIRO' or 'IIRS' header |
| Compression | Lossless Huffman-based compression or uncompressed 12-bit sensor data |
| Byte Endianness | Little-Endian (Intel order) |
| Color Spaces | Olympus Natural RGB, Adobe RGB, sRGB |
| Channels & Structure | 1 channel Bayer mosaic (RGGB) or High-Res Shot multi-exposure sets |
| Max Dimensions | Up to 10368 x 7776 (80 MP Handheld High-Res Shot in OM-1 / E-M1X) |
| Transparency | None |
| Streaming & Progressive | Non-streamable structured TIFF file |
Technical Comparison Matrix: ORF vs Competitors
| Technical Attribute | ORF (Current) | ARW | CR3 | NEF |
|---|---|---|---|---|
| Sensor Format | Micro Four Thirds (2.0x crop factor) | Full-Frame / APS-C | Full-Frame / APS-C | Full-Frame / APS-C |
| Magic Bytes | IIRO / IIRS | II*\0 | ftypcrx | MM\0* or II*\0 |
| Computational Modes | Live ND, Handheld High-Res, Focus Stacking | Pixel Shift (tripod only) | Dual Pixel Raw | Pixel Shift (tripod only) |
| Typical Size (20MP) | 18 MB - 22 MB | 24 MB - 40 MB | 18 MB - 32 MB | 20 MB - 30 MB |
Common Corruption Modes & Hex Recovery Guide
High-Res shot renders blurry or shows ghosted edge artifacts.
Root Cause: Subject motion occurred between sensor-shift exposures during multi-shot ORF capture.
Recovery: Process the ORF using OM Workspace with 'Motion Compensation' enabled or extract normal single-shot base frame.
Security Analysis & Parser Attack Vectors
ORF header structures have unique signature tags and makernote offsets that can lead to out-of-bounds reads in legacy decoders.
Known Attack Vectors
- Buffer over-read when parsing Olympus camera settings makernote tags.
- Integer overflow during multi-exposure High-Res Shot buffer assembly.
- Heap corruption in non-standard Huffman stream decompression.
Defensive Best Practices: Decode ORF files in sandboxed WebAssembly execution contexts.
Historical Origins & Milestones
Key Advantages & Pros
- Supports groundbreaking computational photography features including 50MP/80MP Handheld High-Res Shot.
- Renowned Olympus color science produces vibrant blues and natural foliage greens.
- Embedded lens distortion, chromatic aberration, and shading compensation profiles.
Technical Limitations & Cons
- Micro Four Thirds sensor size produces higher base noise than full-frame RAW files at equivalent high ISOs.
- High-Res Shot ORF files can be massive (exceeding 100 MB per shot) and require specialized processing.
- Older Olympus raw files require proprietary header parsing due to signature variations.
Interesting Technical Trivia
- The magic bytes for ORF are 'IIRO' (Intel byte order, Olympus Raw) or 'IIRS' (Olympus High-Res Shot).
- Olympus pioneered ultrasonic sensor dust reduction, keeping ORF sensors cleaner than any competitor.
- Handheld High-Res Shot takes 16 separate exposures and merges them into a single high-fidelity ORF file.
Frequently Asked Technical Questions
What software opens ORF files?
ORF files can be opened in OM Workspace, Adobe Lightroom, Capture One, Apple Photos, or converted instantly in your browser at File2File.app.
Does OM System still use ORF?
Yes. OM Digital Solutions (OM System) continues to use the ORF format for all OM-series cameras including the OM-1 and OM-5.
What is an Olympus High-Res ORF file?
It is an ORF file containing data from multiple rapid sensor-shift exposures, producing an image with up to 80 megapixels of resolution and full color per pixel.