I shoot all my pictures in the DNG format (supported natively by the Pentax cameras), but they come uncompressed.

I am now going through the process of compressing my entire library using the Adobe DNG Converter (latest version on the Mac OSX Lion) but it seems to be removing some metadata.

When I check the file information (Get Info on the context menu) in Finder, the "More Info" section is empty, as with the original picture I see the photo metadata (aperture, shutter speed, ISO, etc).

Is there a way to keep this metadata?

  • \$\begingroup\$ Which camera do you have and is your firmware up to date? Later model Pentax cameras (K-x and up) do compress them, but may require a firmware update. \$\endgroup\$
    – Joanne C
    Jan 3, 2012 at 14:08
  • \$\begingroup\$ Pentax K10d. It is really uncompressed :( \$\endgroup\$
    – Pablo
    Jan 5, 2012 at 0:42
  • \$\begingroup\$ It would be interesting to know what exiftool says about the metadata of both files. I'd trust exiftool more than Finder (or tools of different OSes). \$\endgroup\$
    – U. Windl
    Jan 16, 2022 at 18:47

1 Answer 1


Okay, I'm going to add this as an answer, since it's an option that's very similar to what you're doing anyways...

Pentax supports both PEF and DNG, and the PEF format is compressed. The Adobe converter will convert PEF over to DNG, with compression, and then there's the ExifTool that you can use to ensure that the metadata is copied over (see the FAQ for details) after the conversion.

Not the most perfect of workflows, but if the conversion works and the metadata is copied, you can then delete the original PEF files and carry on.

It's the only thing I've come up with outside of suggesting buy more disk. :)


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