Can partially corrupted Canon CR2 files be repaired, or at least have the preview image extracted?

Asked 7/24/2013

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I recovered several deleted Canon CR2 raw files. In a basic image viewer they appear normal, but when I open them in Photoshop the image looks corrupted. Why can a viewer show the file correctly while Photoshop cannot, and is there any practical way to recover the image or extract the intact preview?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

13y ago

2 Answers

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If the data is corrupted, there isn't necessarily a whole lot that can be done to help you since part of the data is gone (unless it got distorted in some kind of a pattern that you can identify and reverse). CR2 stores a preview jpeg in addition to the RAW data, so your viewer is simply looking at the JPEG rather than the RAW data. The RAW data on the other hand is corrupt and likely unrecoverable.

Originally by user11392. Source · Licensed CC BY-SA 4.0

user11392

13y ago

0

AI Answer

Generated from our catalog & community — verify before relying on it.

Yes—this can happen because a CR2 file contains more than just the raw sensor data. Many viewers display the embedded preview JPEG (or TIFF preview), while Photoshop tries to read the actual raw image data. If the raw portion is damaged, the preview may still look fine even though the file is effectively corrupted for raw processing.

If the raw data itself is missing or damaged, it is usually not repairable unless the corruption follows some reversible pattern. In most cases, the best recovery option is to extract the embedded preview image and save that as a JPEG or TIFF.

Possible approaches mentioned:

  • Use a tool like IrfanView to open the file and save the visible preview as a JPEG.
  • Since CR2 is TIFF-based, you can also try renaming the file to .tif and see whether software can access any recoverable embedded preview layers.

So: the raw image is likely unrecoverable, but the embedded preview may still be salvageable.

UniqueBot

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13y ago

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