I recently managed to recover my old hard disk where I found my original CR2 and NEF files that I had later moved to a new computer and converted to DNG to earn a little bit more disk space, deleting the original files.

I still kept that old hard disk with the original files but it suddenly stopped working a few years ago. So I only had the DNG files instead of the original camera-created raw files.

A few months ago, though, I managed to rescue that old hard drive with DDrescue and found my originals there. I was wondering whether there was any way to identify those duplicate DNGs in order to delete them and restore the original RAW files in their place now that disk space is not a problem anymore.

Thanks in advance.

  • 1
    \$\begingroup\$ If there’s a lesson in your experience it might be the power of not deleting duplicate copies of pictures. In the future the DNG files might be the best copy you can find. In the present deleting something you might want later is a distinct possibility. \$\endgroup\$ Dec 8, 2020 at 17:02
  • \$\begingroup\$ If one has the originals (and properly practices good backup practices), the DNG files can be recreated at any time. The same can not be said about the reverse. The parts of the maker notes section of the EXIF info that are stripped when converting .cr2 and .nef files to DNG can not be recreated from the .dng files. \$\endgroup\$
    – Michael C
    Dec 9, 2020 at 14:23

1 Answer 1


I use a program called IMatch (from photools.com) to manage my image files (and a few other file types as well). It is called "IMatch" specifically because it was originally based on the author's graduate work on matching images based upon what they looked like, rather than just the arrangement of bits. It does an incredible job of matching images. You can even register some sample images of people's faces and it will identify the people in your pictures (and auto-tag them if you want). It even has a feature where you can literally scribble something that looks vaguely like a picture you remember and it will find the closest matches. It's actually pretty darn good.

It is also a very powerful Digital Asset Management (DAM) tool. It now incorporates EXIFtool for all of its manipulation of metadata, so you know it is modifying the metadata in an industry standard manner. It has no image manipulation features, like Lightroom does (other than basic file resizing). But I prefer to keep those two major functions separate. Instead, it has categorization tools that I feel are much better than Lightroom's. (Of course, I haven't looked at Lightroom in years.)

As I mentioned, it will also manage other types of files. If that file type does not use EXIF metadata, then the program will create "sidecar" files to store that data. Of course, all that data is also stored in the program's database. But the author feels very strongly about always giving you full control of your data, so it mirrors that data to the metadata in the files, or those sidecar files.

The best feature of this software is that there is no frikkin' subscription. It is a one-time cost of about $150, and that is well worth it.


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