Canon RAW 2

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== Sample files ==
 
== Sample files ==
* https://telparia.com/fileFormatSamples/image/cr2/
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* {{DexvertSamples|image/cr2}}
  
 
== References ==
 
== References ==

Latest revision as of 02:56, 28 December 2023

File Format
Name Canon RAW 2
Ontology
Extension(s) .cr2
PRONOM fmt/592
Wikidata ID Q27866048
Released 2001

Canon RAW 2 (CR2) is a raw image format used by Canon cameras. It replaced CRW, starting with the 20D, 350D/Digital Rebel Xt and 1D. It was replaced by Canon RAW 3.

Contents

[edit] Organization

Canon CR2 files are TIFF files. All is organised in a TIFF / IFD file.

On of the differentiation with the CR2 files is that they have a header before the IFD0. This does not violate the TIFF spec.

offset length description
0 8 TIFF header
8 2 literal 'CR'
10 1 major version (2)
11 1 minor version (0)
12 4 (long) for the offset of the IFD3 that contain the RAW data. (in the TIFF byte order)

Exif is attached to the ExifIFD of IFD0. The CFA data is in IFD3.

[edit] Compression

Canon CR2 files use the old original Lossless JPEG standard for the RAW data. The same used by Adobe DNG.

Source: http://www.adobeforums.com/cgi-bin/webx/.3bc36454/0 (link dead)

The width dimension specified in the JPEG stream is actually half the reality because it takes into account 2 channels per sample (the dimension of the CFA pattern).

350D, 5D and 30D files have a different layout. IFD3 (where the CFA is located) has the tag 0xc640 that contains 3 SHORT. 1, x, y. x is the number of column of the first "slice" of the image, y is for the second "slice". I don't know what the 1 mean.

The slicing means that the output scanlines have to be reorganised as they are shorter to have a top -> bottom then left -> right, a bit like columns of text. (TODO: do a nice diagram)

[edit] Modified files

Apparently Canon's proprietary software modifies the RAW file. Other proprietary software seems to choke on said modified files (https://web.archive.org/web/20150512011452/http://www.prophotohome.com/forum/raw-photo-processing-software-technique/62864-cr2-raws-converted-dpp-won-t-open-aperture.html).

ExifTool has some info:

[edit] Sample files

[edit] References

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