Camera Image File Format

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File Format
Name Camera Image File Format
Extension(s) .crw
MIME Type(s) image/x-canon-crw
LoCFDD fdd000241
PRONOM fmt/593
Released 1997

The Camera Image File Format, sometimes called the Canon RAW (CRW) format, was used by some early Canon digital cameras. It was replaced by the CR2 format starting with the EOS 20D in 2004. The .crw extension is sometimes used by CHDK, but this is a different file format.



The original CRW file format was used on Canon's early x86-based cameras running Datalight ROM-DOS, from 2000 to 2004. All the early Canon digital SLRs used this format, and some compact cameras did too. The following cameras can generate files in the CRW format:

  • Canon EOS D30 (2001), the first all-Canon DSLR. Not to be confused with the 30D, which is a completely different camera.
  • Canon EOS D60 (2002), not to be confused with the 60D, which is a completely different camera
  • Canon EOS 10D (2003)
  • Canon EOS 300D (2003), a very close relative of the 10D.
  • Canon PowerShot G1, G2, G3, G4, G5, and G6 (2000-2004), high-end compact cameras.
  • Canon PowerShot S30, S40, S50, S60, and S70 (2001-2004)

File header

A Canon CRW file always begins with the following byte sequence: 49 49 1A 00 00 00 48 45 41 50 43 43 44 52. This is explained below:

Bytes Value Description
49 49 "II" "II" for Intel byte-order, i.e. little endian. All cameras that use the CRW format have little-endian x86 processors, and this value is always "II".
1A 00 00 00 0x0000001a 32-bit integer giving the length of the CRW header. This is always 0x0000001a, i.e. 26 bytes.
48 45 41 50 43 43 44 52 "HEAPCCDR" Identifies the file as a Canon CRW raw file.

Software support

Dave Coffin's dcraw utility, on which many other raw decoders are based, can decode all Canon CRW files.

Adobe's Camera Raw plugin supports CRW files. They should open fine in Lightroom, Aperture, and other commercial tools.

All the well-known open source tools, like Darktable and RawTherapee, can open and convert CRW files.

Phil Harvey's ExifTool can read EXIF data from CRW files.

Canon distributes Canon Utilities RAW Image Converter free for Windows.


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