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.cr2 File Extension

Learn what a .cr2 file is, how to open Canon RAW photos, how Poly supports them, and which format to use when sharing.

File extension details for .cr2

Full Support
File typeCanon Raw 2 photograph
MIME type
image/x-canon-cr2
EncodingBinary, TIFF-based camera RAW with Exif, Canon metadata, and embedded JPEG previews
Operating systemsWindows, macOS, Linux, iOS, iPadOS
Opens withCanon Digital Photo Professional, Adobe Lightroom, Adobe Camera Raw, Apple Photos
Poly supportYes. Poly provides rich support for Canon CR2 photos.
Indexed by PolyYes. Poly indexes filenames, available camera metadata, color, and visual similarity.
Preview in PolyYes. CR2 files open in Poly's image viewer.
Poly agentYes. The Poly agent can understand the visible photograph.

What kind of file is a .cr2?

A .cr2 file is a Canon Raw 2 photograph. It preserves minimally processed sensor measurements and camera metadata so you can decide white balance, exposure, color, noise reduction, and sharpening during development. A camera-finished JPEG is easier to share, but offers less editing latitude.

The conventional image/x-canon-cr2 MIME type is not registered by IANA.1 CR2 is TIFF-based. A common little-endian file begins with 49 49 2A 00 10 00 00 00 43 52 02 00: a TIFF header followed at byte 8 by CR and version 2.0.2 Ordinary TIFF and other camera RAW files can share the first four bytes, so reliable identification checks the longer structure and camera metadata.

Renaming a JPEG, TIFF, CRW, or CR3 file to .cr2 does not convert it. The filename alone cannot prove that the contents are a valid Canon RAW photo.

How do I open a .cr2 on my computer?

Use software that supports the exact Canon camera model:

  • Windows or macOS: Canon Digital Photo Professional (DPP) opens and develops compatible CR2 images.3
  • Windows or macOS: Adobe Lightroom and Camera Raw support many Canon models. Adobe lists the minimum compatible version for each camera.4
  • macOS, iOS, and iPadOS: Apple provides system RAW support for listed Canon cameras, which compatible apps can use.5
  • Linux: RAW editors such as darktable or RawTherapee may open CR2 files, with support varying by camera.

Web browsers do not natively develop CR2 photos. Export a JPEG, WebP, AVIF, or PNG copy for a website.

If an editor opens CR2 files from one camera but not another, update its RAW support before assuming the file is damaged. Camera-model compatibility matters as much as the suffix.

Poly support for .cr2

Poly gives CR2 photographs thumbnails, an in-app image preview, available Exif metadata, visual search, and agent understanding. You can find a capture by filename, metadata, color, or visible content, and the Poly agent can reason about the displayed photograph.

The preview represents a camera-rendered image embedded in the file, not a new development of the sensor measurements. Use a dedicated RAW editor for adjustments such as highlight recovery and white balance. Words photographed inside a CR2 are not indexed as document text. Review timestamps, camera details, serial information, and location metadata before sharing an original.

History of .cr2

CR2 succeeded Canon's older, CIFF-based CRW format. libopenraw identifies the EOS 20D and EOS 350D/Digital Rebel XT generation among the cameras that introduced CR2.2 Canon records a September 2004 market date for the EOS 20D, whose manual names .CR2 as its RAW extension.6

Canon later replaced CR2 with CR3 on newer cameras. The formats use different containers: CR2 is TIFF-based, while CR3 uses an ISO base media file container. Existing Canon cameras and photo archives still make CR2 an important working format.

Working with .cr2 and alternatives

Keep the original CR2 as the master, then export a version suited to its destination:

FormatBest forTradeoff
JPEGEmail, galleries, and broad compatibilityLossy; much RAW editing latitude is gone
TIFFHigh-quality interchange and further editingLarge rendered file
DNGRAW-oriented workflows in compatible softwareDifferent container; validate camera-specific behavior
PNGLossless sharing of a finished renderingDoes not preserve the original sensor workflow

Canon DPP can save developed RAW images as JPEG or TIFF.7 Keep the CR2 after export because a rendered derivative cannot recreate the original sensor measurements.

Footnotes

  1. Internet Assigned Numbers Authority. Media Types Registry. The image registry contains no image/x-canon-cr2 registration. ↩
  2. libopenraw. Canon CR2. Documents the conventional MIME type, TIFF/IFD layout, CR2 header, Exif location, RAW compression, and early camera models. ↩ ↩2
  3. Canon. Digital Photo Professional: Supported Image Formats. Lists .CR2 among supported Canon RAW extensions. ↩
  4. Adobe. Cameras Supported by Camera Raw. Lists supported Canon models and minimum Camera Raw versions. ↩
  5. Apple Support. Digital Camera RAW Formats Supported by Apple Operating Systems. Lists camera-specific Canon RAW support. ↩
  6. Canon Camera Museum. EOS 20D; Canon. EOS 20D Instruction Manual. ↩
  7. Canon. Digital Photo Professional: Saving as JPEG or TIFF Images. ↩
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