Canon RAW 2
(Dumped info from http://libopenraw.freedesktop.org/wiki/Canon_CR2 - I am the author.) |
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|formattype=electronic | |formattype=electronic | ||
|subcat=Cameras and Digital Image Sensors | |subcat=Cameras and Digital Image Sensors | ||
| + | |released=2001 | ||
| + | |extensions={{ext|cr2}} | ||
| + | |pronom={{PRONOM|fmt/592}} | ||
| + | |wikidata={{wikidata|Q27866048}} | ||
}} | }} | ||
| + | '''Canon RAW 2''' ('''CR2''') is a raw image format used by Canon cameras. It replaced [[Camera Image File Format|CRW]], starting with the 20D, 350D/Digital Rebel Xt and 1D. It was replaced by [[Canon RAW 3]]. | ||
| − | + | == Organization == | |
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Canon CR2 files are TIFF files. All is organised in a TIFF / IFD file. | Canon CR2 files are TIFF files. All is organised in a TIFF / IFD file. | ||
| − | On of the | + | On of the differentiation with the CR2 files is that they have a header before the IFD0. This does not violate the TIFF spec. |
{| | {| | ||
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| 0 || 8 || TIFF header | | 0 || 8 || TIFF header | ||
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| − | | 8 || 2 || | + | | 8 || 2 || literal 'CR' |
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| 10 || 1 || major version (2) | | 10 || 1 || major version (2) | ||
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Exif is attached to the ExifIFD of IFD0. The CFA data is in IFD3. | Exif is attached to the ExifIFD of IFD0. The CFA data is in IFD3. | ||
| − | + | == Compression == | |
| − | + | Canon CR2 files use the old original [[Lossless JPEG (original)|Lossless JPEG]] standard for the RAW data. The same used by [[DNG|Adobe DNG]]. | |
| − | Canon CR2 files use the old original [[Lossless JPEG]] standard for the RAW data. The same used by [[DNG|Adobe DNG]]. | + | |
Source: http://www.adobeforums.com/cgi-bin/webx/.3bc36454/0 (link dead) | Source: http://www.adobeforums.com/cgi-bin/webx/.3bc36454/0 (link dead) | ||
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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) | 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) | ||
| − | + | == Modified files == | |
| − | Apparently Canon's proprietary software modifies the RAW file. Other proprietary software seems to choke on said modified files (http://www.prophotohome.com/forum/raw-photo-processing-software-technique/62864-cr2-raws-converted-dpp- | + | 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: | ExifTool has some info: | ||
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* http://www.cpanforum.com/threads/5170 | * http://www.cpanforum.com/threads/5170 | ||
| − | === | + | == Sample files == |
| + | * {{DexvertSamples|image/cr2}} | ||
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| + | == References == | ||
* http://lclevy.free.fr/cr2/ | * http://lclevy.free.fr/cr2/ | ||
* http://web.archive.org/web/20061125031802/http://crousseau.free.fr/imgfmt_raw.htm (in French, by one of the developers of DxO) - Using the wayback machine ! | * http://web.archive.org/web/20061125031802/http://crousseau.free.fr/imgfmt_raw.htm (in French, by one of the developers of DxO) - Using the wayback machine ! | ||
| + | * [https://github.com/lclevy/libcraw2/blob/master/docs/cr2_poster.pdf CR2 format documentation poster] | ||
| + | * [https://twitter.com/lorenzo2472/status/536569538083844098/photo/1 Format poster image] | ||
| + | * [http://web.archive.org/web/20140219063611/http://wildtramper.com/sw/cr2/cr2.html Canon's CR2 Raw File Format Specification] | ||
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| + | [[Category:TIFF]] | ||
Latest revision as of 02:56, 28 December 2023
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
- http://lclevy.free.fr/cr2/
- http://web.archive.org/web/20061125031802/http://crousseau.free.fr/imgfmt_raw.htm (in French, by one of the developers of DxO) - Using the wayback machine !
- CR2 format documentation poster
- Format poster image
- Canon's CR2 Raw File Format Specification
