{"id":"image-x-olympus-orf","mimeType":"image/x-olympus-orf","name":"Olympus Raw Format","shortName":"Olympus-ORF","category":"Photography \u0026 Raw Imaging","extensions":[".orf"],"description":"The image/x-olympus-orf MIME type represents the Olympus Raw Format (ORF). Developed by Olympus Corporation (and now maintained by OM Digital Solutions), ORF is a proprietary raw image format utilized across Olympus digital cameras, including the OM-D, PEN, and classic E-System series. Structurally based on the TIFF specification but featuring unique proprietary headers, an ORF file stores uncompressed or losslessly compressed raw pixel data directly from the camera's sensor. This format preserves maximum dynamic range, precise 12-bit color depth, and essential EXIF metadata required for high-fidelity post-processing.","seo":{"title":"image/x-olympus-orf MIME Type | Developer Reference for Olympus ORF","description":"Complete reference for the image/x-olympus-orf MIME type: Olympus Raw Format (ORF), OM Digital Solutions, TIFF structure, and file detection.","faqs":[{"question":"What is an Olympus ORF file?","answer":"An ORF (Olympus Raw Format) file is a raw image generated by Olympus and OM System digital cameras. It contains unprocessed sensor data, offering significantly higher dynamic range, detail, and color depth compared to a standard compressed JPEG image."},{"question":"How do I open an ORF file?","answer":"Because ORF is a raw format, standard web browsers and basic image viewers often cannot render it natively. You need specialized software like OM Workspace, Adobe Lightroom, Adobe Photoshop (via Camera Raw), Capture One, or open-source alternatives like RawTherapee."},{"question":"Are ORF files just standard TIFFs?","answer":"While ORF files are built upon the TIFF container architecture, they utilize proprietary magic headers (like 'IIRO' or 'MMOR') instead of standard TIFF signatures. They also contain proprietary Olympus MakerNote metadata necessary for proper raw demosaicing."}]},"index":{"compression":["Uncompressed","Proprietary Lossless"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Professional Digital Photography","Non-destructive Image Post-Processing","High Dynamic Range (HDR) Imaging Archival"]},"technical":{"magicBytes":{"hex":"49 49 52 4F (IIRO) or 4D 4D 4F 52 (MMOR) or 49 49 53 52 (IIRS)","ascii":"IIRO or MMOR or IIRS"},"container":"TIFF-based (with proprietary variants)","compressionAlgorithm":["None","Olympus Proprietary Lossless"],"colorDepth":["12-bit (Per Channel)"],"transparency":false,"animation":false,"metadata":{"exif":true,"xmp":true,"iccProfile":true},"alphaChannel":false,"progressiveLoading":false,"hdrSupport":true},"history":{"developer":"Olympus Corporation (Now OM Digital Solutions)","released":"2000","specification":"Proprietary (Reverse-engineered by the community / LibRaw)"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"OM Workspace","logo":""},{"name":"Adobe Lightroom Classic / CC","logo":""},{"name":"Capture One","logo":""},{"name":"RawTherapee","logo":""}],"conversion":{"convertTo":["dng","jpeg","tiff","png"],"convertFrom":[]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/x-olympus-orf"}],"htmlAccept":"image/x-olympus-orf, .orf","fileDetection":["Unlike many other raw formats (like Canon CR2 or Nikon NEF) that strictly use the standard TIFF magic bytes (49 49 2A 00), Olympus ORF files utilize unique 4-byte ASCII identifiers.","Check the first 4 bytes for specific Olympus signatures such as 'IIRO' (Hex: 49 49 52 4F), 'MMOR' (Hex: 4D 4D 4F 52), or 'IIRS' (Hex: 49 49 53 52).","Some older variants may also begin with 'II+M' (Hex: 49 49 2B 4D). Because of these distinct headers, programmatic identification of ORF is generally more reliable than other TIFF-based raw formats."]},"prosCons":{"pros":["Retains maximum sensor data, allowing extreme recovery of highlights and shadows that would be permanently lost in a JPEG","White balance, sharpening, and color profiling are saved as metadata instructions, meaning they can be completely altered in post-production","Unique magic byte signatures make programmatic file sniffing highly reliable compared to other camera manufacturers' TIFF-spoofing headers"],"cons":["Proprietary format means it requires constant updates to raw processing engines every time a new camera model is released","Produces very large file sizes (often 15MB to 30MB+ per image depending on sensor resolution)","Cannot be directly embedded into web pages or used in standard HTML/CSS contexts"]},"specifications":{"url":"https://www.libraw.org/","rfc":"","mimeAliases":["image/orf"]},"developerSnippets":{"python":"import magic\n# Libmagic natively detects the 'IIRO', 'IIRS', and 'MMOR' signatures as Olympus raw files\nprint(magic.from_file('photo.orf', mime=True)) # Outputs 'image/x-olympus-orf'","nodejs":"const fs = require('fs');\n// Manually detecting the 4-byte Olympus ORF magic signatures\nconst buffer = Buffer.alloc(4);\nconst fd = fs.openSync('photo.orf', 'r');\nfs.readSync(fd, buffer, 0, 4, 0);\nfs.closeSync(fd);\nconst signature = buffer.toString('ascii');\nconst isORF = ['IIRO', 'MMOR', 'IIRS', 'II+M'].includes(signature);\nconsole.log('Is Olympus ORF:', isORF);","go":"import (\n    \"bytes\"\n    \"net/http\"\n)\n// Native Go HTTP detection will likely return application/octet-stream.\n// Check directly for the explicit 4-byte Olympus signatures:\n// isORF := bytes.HasPrefix(buf, []byte(\"IIRO\")) || bytes.HasPrefix(buf, []byte(\"MMOR\")) || bytes.HasPrefix(buf, []byte(\"IIRS\"))","php":"$mime = mime_content_type('photo.orf');\necho $mime; // Standard PHP setups with updated magic definitions will return 'image/x-olympus-orf'"},"relatedFormats":["dng","tiff"]}