On Sep 14, 2005, at 6:48 AM, Martin Trautmann wrote:
I guess this could include
- sensor faults (defective, calibration)
- image info (lense model, aperture, time, focal length, distance)
Yes.
I guess it should be a simple task to build a poor lense with strong
vignetting or strong distortions - and compensate most of these
flaws by
software later on? This would require some kind of reasonable
characterisation how to compensate those flaws.
Not a "simple" task, but doable task. This is indeed what software
like "DxO Optics Pro" is designed to do.
I guess part of it is the reasons for proprietary raw formats.
Lens characterization data is not embedded into RAW data format
files, only sensor characterization data. Lens characterization data
can be quite voluminous and varies on a lens by lens basis if you're
really looking to do the best job.
http://openraw.org/faq/?id=14 does not show that many infos about
What is metadata and what is it good for?
Metadata is a very general term. It runs the gamut of stuff that
falls into the EXIF data structures, stuff that is outside EXIF but
necessary to processing, stuff that is informational only ...
basically, metadata can contain anything a camera manufacturer wants
to put in there, for present or future use.
I don't know how much of this error correcting options are used now
and will
be used in the future. But I wonder how big this portion of raw
info is, the
more detailed it becomes.
The metadata size isn't terribly large as most of it can be coded
into simple numeric terms that are decoded when it is extracted.
... RAW standards ...
I wonder whether they are sufficient for all the manufacturer's
needs. The
current abuse of EXIF "maker notes" is a sign that either the
standard is
not suited very well, or manufacturers don't mind the standards.
As I intimated, these RAW standards efforts are not yet mature. And
there is good argument to the effect that there is always a need for
a manufacturer to be able to inject some arbitrary bits of
information into the metadata for future use as the technology and
standards progress. I don't see the use of "maker notes" in EXIF or
RAW to be an abuse: it's simply that the standard represents a
greatest common denominator for the data that ought to be included,
and most manufacturers feel there is a need for additional, more
specific data germaine to their needs.
Godfrey
