[Rawstudio-dev] Olympus E-1 files have strong green cast
anders at kvistmail.dk
Thu Apr 17 10:06:26 CEST 2008
Olli Hänninen wrote:
> Hi Anders,
> Thank you for your answer.
> Well...first of all, we haven't got any code to read meta from
> .orf files yet - so we cannot read the values for camera
> whitebalance yet. We will take a look at this as in the near future.
> Just to get to know the current situation, I'd like to ask is this the
> case with just few cameras (for example Olympus), or is this the case
> with the vast majority of cameras? There is an option -w in dcraw that
> you can use to set camera white balance (if possible). Doesn't this
> help at all? And one more question: does Rawstudio extract meta data
> by using dcraw or ExifTool by Phil Harvey
> (http://www.sno.phy.queensu.ca/~phil/exiftool/) or by some other means?
This is only a few cameras. We have mainly had our focus on easy wins
and Canon and Nikon as they are the mostly used. We do the reading of
metadata by ourself, so we'll "just" have to check the dcraw code and
create a metadata loader for olympus cameras too.
> One thought. Would it be a good or silly idea to add yet another
> "camera white balance" setting that would use reverse engineering? I
> mean, all raw-files have embedded thumbnails. We could have a piece of
> code that analyzes the thumbnail's color properties (i.e. darkest and
> lightest point for R, G and B) and then sets same values for the
> raw-photo. In other words, the resulting histogram of the raw-photo
> would roughly be equal to the thumbnail. This way, we would have at
> least some kind of camera white balance for all cameras without need
> to write specific code for each camera model and make. Or would this
> mean more work than tailoring the code for all cameras?
That was a thought we had when we first started out. But it wasn't that
bad to read the camera white balance from metadata when we also needed
other metadata from the raw files. We never tried using the procedure
you've mentioned, but it could be used as a fallback to cameras that
leaves no camera wb in metadata - if they have a thumbnail or embedded
jpeg :) One thing i don't really like about it, is that a thumbnail is
very much reduced in size and a lot of pixels has been cut away, and
could leave us with RGB values thats never gonna match a full size photo
and again will leave us with a odd camera wb...
> Olli H.
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