First off, the original capture file is the source ... How could you "extract
more metadata in the process" of converting from PEF to DNG?
I'm referring to the closed-nature of some of the metadata in the
EXIF of the RAW file. Of course there's no "more" data (other than
whatever the DNG conversion might want to record about itself). What it
*might* allow is open-access to some of the unknown data. I've tried to
contact Pentax to get more information on the "VendorTAG"-type EXIF tags,
with little success. If one proprietary company (Adobe) manages to
beg/borrw/steal/reverse-engineer/buy the ability to read this stuff and
put it in an open-format like DNG, I consider that more data.
DNG conversion
simply moves all the existing metadata into the DNG format, along with the
sensor data. The real advantage of the DNG format, aside from taking up less
space through applying lossless compression to the sensor data, is that it
was designed to be a container format so more metadata can be added to the
RAW file itself (RAW processing parameters, IPTC data, etc) without otherwise
affecting the RAW data at all. So ultimately a DNG file usually has more
metadata in it but the additions come from processing with savvy
applications, not from the original RAW format file.
Godfrey
As a wrapper, that's fine. The way I understood it (which could
be way off since I've never even played with it since I cannot), was one
could a) convert to DNG, or b) throw the original RAW file in as well.
If I was guaranteed I could always reverse the process through an
open-source means, option a) would be a viable archival method to get the
compression and pseudo-application-agnostic qualities. Option b) seems
like a silly idea for archival since it takes up even more space than
the original file.
-Cory
--
*************************************************************************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
*************************************************************************
