A CR2 file is a raw photo from a Canon camera. It holds the sensor data almost exactly as the camera read it, before white balance, sharpening, Picture Style and JPEG compression were applied. Canon EOS cameras wrote CR2 from 2004 until the move to CR3 in 2018, so a CR2 on your disk most likely comes from an EOS DSLR such as a 5D, 6D, 7D, 80D or one of the Rebel/Kiss models, or from an older photo archive.
From CRW to CR2 to CR3
Canon's first raw format, CRW, used Canon's own CIFF container. In 2004 the EOS-1D Mark II and EOS 20D switched to CR2, short for Canon Raw version 2, which is built on TIFF. It stayed in use for some fifteen years. In 2018 the EOS M50 introduced CR3, a container derived from the ISO base media file format, the same family as MP4. All newer Canon bodies write CR3, while DSLRs released before then, including the EOS 2000D and 4000D from 2018, keep writing CR2. Canon has never published the specification. Everything the open-source tools know about CR2 comes from reverse engineering.
What is inside a CR2 file
- A TIFF file with a signature. Right after the 8-byte TIFF header come the letters
CRand the version number 2.0. That is how software tells a CR2 from an ordinary TIFF. - Several images in one file. A full-size JPEG preview, a small thumbnail and the raw sensor data. Quick viewers and the camera's own playback show the JPEG preview, not the raw data.
- Lossless compression. The sensor data is compressed with the original lossless JPEG method (ITU-T T.81), the same one DNG uses. No detail is lost. Older bodies record 12 bits per pixel, models from 2007 on (EOS 40D, EOS-1D Mark III) 14 bits.
- Metadata. EXIF plus Canon maker notes: lens, Picture Style, autofocus points, and more.
- Variants. Some bodies offer smaller sRAW and mRAW files. These are already demosaiced, so they are not true raw data in the usual sense. Dual Pixel RAW on the EOS 5D Mark IV stores two sub-images and makes the file roughly twice as large.
How to open CR2 files
- Canon Digital Photo Professional (Windows, macOS) is free for Canon owners. The download page may ask for the camera's serial number. It reproduces Picture Styles exactly as the camera does.
- Windows 10 and 11: install the free Raw Image Extension from the Microsoft Store. Photos then opens CR2 files and File Explorer shows thumbnails.
- macOS and iPhone/iPad: Preview and Photos read CR2 from supported cameras without extra software.
- Linux: darktable and RawTherapee are free, full raw editors. Most image viewers on Linux show at least the embedded preview.
- Adobe Lightroom and Photoshop open CR2 through Camera Raw, including on Android and iOS in Lightroom mobile.
Common CR2 problems
CR2 won't open in Photoshop
Your Camera Raw plug-in is older than the camera. Update Photoshop, or if you are on an old version you cannot update, convert the files to DNG with the free Adobe DNG Converter and open those.
The photo looks different than on the camera screen
The camera displays the embedded JPEG with your Picture Style, Auto Lighting Optimizer and lens corrections applied. Third-party raw editors start from their own neutral rendering. This is not damage. Digital Photo Professional shows the image the way the camera intended.
CR2 file corrupted or half grey
Usually a card read error or an interrupted copy. Copy the file again with a card reader. If the raw data really is damaged, the preview often survives: exiftool -b -PreviewImage photo.CR2 > photo.jpg saves it as a full-size JPEG.
Converting CR2
CR2 is usually converted to JPG for sharing and printing, to TIFF for programs without raw support, and to DNG for long-term archiving. Our converter develops the file with camera white balance, standard demosaicing, sRGB colours, 8 bits per channel, full sensor resolution. Picture Style, lens corrections, noise reduction and highlight recovery are not applied, so the result looks more neutral and a little flatter than the camera JPEG. Full EXIF and maker notes are not carried over. Details are on CR2 to JPG. If you still want to edit exposure and colour, develop the raw yourself in a raw editor and export a 16-bit TIFF.
Other camera raw formats: NEF (Nikon), ARW (Sony), PEF (Pentax).
Quick facts
| Developer | Canon |
|---|---|
| First used | 2004 (EOS-1D Mark II, EOS 20D) |
| Successor | CR3 (since 2018, EOS M50) |
| Type | Camera raw image, TIFF-based, proprietary, no public specification |
| Compression | Lossless JPEG (ITU-T T.81) |
| Bit depth | 12 or 14 bits per pixel |
| Typical use | Raw photos from Canon EOS DSLRs |
Further reading: Camera raw formats at the Library of Congress, CR2 structure documented by libopenraw.