pef vs dng

Godfrey DiGiorgi gdigiorgi at gmail.com
Mon Oct 5 17:15:15 EDT 2009


On Mon, Oct 5, 2009 at 1:20 PM, Dario Bonazza <dario.bonazza at virgilio.it> wrote:
> Godfrey DiGiorgi wrote:
>
>> ALL versions of the DNG specification since LR 1.0 was released
>> capture all of the data in the native RAW-PEF files.
>
> I have no reason for not believing you, but I'm sure for some long time I
> couldn't find the metadata in DNG files, and that was truly disappointing.

There's no reason for belief ... I have proof right here. I have
*every* version of Lightroom that ever existed, including back to the
pre-Public Betas, and I have Pentax K10D PEF and DNG files from when
the K10D first shipped. I can't explain why you had some oddball
problem.

I am not recommending DNG. Larry asked if there were any disadvantages
to using DNG. In my experience and testing, the only disadvantage is
the amount of space they consume on the camera storage card. There is
no data loss, and there are techniques to apply compression to them
that are foolproof and already a part of the software which he has in
hand, so there's no additional cost.

My workflow with the K10D, AFTER Lightroom 1.0 shipped, was to capture
in PEF and convert to DNG on import to Lightroom. This optimized
storage on the cards and provided the DNG files for processing work. I
archived all the PEFs. In three plus years, I have yet to go back and
look at a single one of the original PEF files for anything but
testing.

Why should one put files into DNG format?

- Because it is a publicly specified RAW file format that continues to
grow in popularity.
- Because it does very good lossless compression of many uncompressed
native RAW formats.
- Because it is a container file format which can contain additional
information added to the RAW format data (like IPTC metadata,
rendering instructions, etc, even the original native RAW file for
archival storage) without having to manage pairs of files (native PEF
and .XMP sidecar).

And perhaps other reasons as well.

Whether these benefits mean enough for you to consider using the DNG
files is your business. I use it, have been using it, since 2005. Its
compression over Pentax *ist DS PEFs, Panasonic .RAW and .RW2, Minolta
.MRF, Olympus .ORF, has saved well over 250 Gbytes of storage space in
my archives.
-- 
Godfrey
  godfreydigiorgi.posterous.com




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