.ORF

Introduction

ORF is the raw photo format of Olympus digital cameras. Olympus sold its camera business in 2021, and the cameras made since under the OM System name still write .orf files. The file holds the data from the camera’s sensor before any processing, with the camera settings and a JPEG preview.

Olympus has not published the format.

Structure

An ORF file is laid out like a TIFF file, with image file directories (IFDs) of tags that point to the previews, the Exif data with the Olympus maker note, and the raw sensor data. The header differs from TIFF in one detail: in place of the TIFF magic number 42, most files start with IIRO (49 49 52 4F), and some with IIRS or the big-endian MMOR. Readers that only accept standard TIFF headers reject the file.

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