CR3 (.cr3)

.cr3 file signature | image/x-canon-cr3

CR3 is Canon’s RAW image file format, developed and maintained by Canon for storing unprocessed data from compatible digital cameras. It is used for high-quality photo capture, post-processing, and archival workflows in Canon camera software and third-party image editors that support Canon RAW files. The format is current and widely used; like other RAW files, it is generally safe to view, though untrusted files should be opened with updated software.

Safe

Magic Bytes

Offset 4


              66 74 79 70 63 72 78 20

Sources: Apache Tika

All Known Signatures

3 signature variants are documented for .cr3 files across multiple sources.

Hex Signature	Offset	Sources
66 74 79 70 63 72 78 20	4	Apache Tika
66 74 79 70 63 72 78	0	Wikipedia
43 52	0	Wikipedia

Extension

.cr3

MIME Type

image/x-canon-cr3

Byte Offset

Risk Level

Safe

Validation Code

How to validate .cr3 files in Python

Python

def is_cr3(file_path: str) -> bool:
    """Check if file is a valid CR3 by magic bytes at offset 4."""
    signature = bytes([0x66, 0x74, 0x79, 0x70, 0x63, 0x72, 0x78, 0x20])
    with open(file_path, "rb") as f:
        f.seek(4)
        return f.read(8) == signature

How to validate .cr3 files in Node.js

Node.js

function isCR3(buffer: Buffer): boolean {
  const signature = Buffer.from([0x66, 0x74, 0x79, 0x70, 0x63, 0x72, 0x78, 0x20]);
  if (buffer.length < 12) return false;
  return buffer.subarray(4, 12).equals(signature);
}

How to validate .cr3 files in Go

func IsCR3(data []byte) bool {
    signature := []byte{0x66, 0x74, 0x79, 0x70, 0x63, 0x72, 0x78, 0x20}
    if len(data) < 12 {
        return false
    }
    return bytes.Equal(data[4:12], signature)
}

API Endpoint

GET /api/v1/cr3


              curl https://filesignature.org/api/v1/cr3

See the full API documentation for all endpoints and parameters.

Related Formats

.avif .heic .heif .bmp .cr2 .dib

Frequently Asked Questions

What is a .cr3 file?

A .cr3 file is identified by the magic bytes 66 74 79 70 63 72 78 20 at byte offset 4. CR3 is Canon’s RAW image file format, developed and maintained by Canon for storing unprocessed data from compatible digital cameras. It is used for high-quality photo capture, post-processing, and archival workflows in Canon camera software and third-party image editors that support Canon RAW files. The format is current and widely used; like other RAW files, it is generally safe to view, though untrusted files should be opened with updated software.

What are the magic bytes for .cr3 files?

The magic bytes for CR3 files are 66 74 79 70 63 72 78 20 at byte offset 4. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .cr3 file?

To validate a .cr3 file, read the first bytes of the file and compare them against the known magic bytes (66 74 79 70 63 72 78 20) at offset 4. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .cr3 files?

The primary MIME type for .cr3 files is image/x-canon-cr3.

Is it safe to open .cr3 files?

CR3 (.cr3) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.