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Re: [OCLUG-Tech] raw conversion problem

On Tue, Nov 03, 2009 at 09:15:03PM -0500, Brenda J. Butler wrote:
> I use convert, from imagemagick.  From dpkg -L imagemagick:
> 
> /usr/bin/composite
> /usr/bin/mogrify
> /usr/bin/display
> /usr/bin/compare
> /usr/bin/convert
> /usr/bin/import
> /usr/bin/montage
> /usr/bin/animate
> /usr/bin/conjure
> /usr/bin/stream
> /usr/bin/identify
> 
> Give it a try and see if the quality is good enough for you.

Wow, I didn't know it could do the conversions from Canon RAW (CRW and
CR2) as well.  Neat...

> I see it does understand .nef files (according to
> http://www.imagemagick.org/script/formats.php).  I just
> use it to resize and rotate pictures.
> 
> I'm curious as to how it will compare with dcraw for your
> purposes.

I've been using ufraw-batch for batch processing.  The newest bleeding
edge version has support for my Canon EOS 5DmarkII (I sent in the white
balance preset profiles) and has liblensfun, which allows corrections
for lens geometry and aberrations. I find I get best results for white
balance when I use a grey card with the subject lighting, or find one
image in a batch that has pure white in it that is not overexposed and
do a test ufraw on it with the eyedropper to get the colour temperature
and tint (green component).  The auto white balance on my camera is not
as great and consistent as could be desired and has troubles with
environmental extremes.  It does poorly in dawn or dusk and in candle
light, incandescent and fluorescent light.

I do something like:

	temperature=2555;green=0.928
	for i in *.cr2
	do
		ufraw-batch \
			--exposure=1.33 \
			--temperature=$temperature \
			--green=$green \
			--black-point=0 \
			--saturation=1.8 \
			--compression=93 \
			--out-type=jpeg \
			--output=${i%cr2}jpg \
			--clip=film \
			$i
	done

If the image hasn't got many highlights, I'll set --clip=digital and
lower the saturation a bit.

As for the sharpness, that one I haven't found an easy answer yet, but
have found a few gimp plugins that are an improvement over "sharpen" and
"unsharp mask".

I find that the stock .jpg ouput of my camera is a bit oversaturated...

I'll have to look at ifrview...

I've not used colour profiles yet...

Ufraw also supports black frames, presumably to compensate for dead
pixels.

> bjb
> 
> 
> On Tue, Nov 03, 2009 at 07:01:43PM -0500, Peter Sjoberg wrote:
> > I'm trying to find the best way to convert my raw pictures to jpeg in
> > batch.
> > The most obvious answer (for readers of this list) is to use dcraw but I
> > find the colours to be washed out unless I manually adjust each picture
> > - not an option for batch mode.
> > As a test I did use 5 different ways to convert various pictures and put
> > them up on
> > http://www.techwiz.ca/~peters/raw/index.html
> > 
> > 
> >      1. the raw .nef picture
> >      2. m1 dcraw-plain 
> >      3. m2-dcraw-embedded (-e) 
> >      4. m3-ifrview - 
> >      5. m4-ViewNX - the manufacture provided sw 
> >      6. m5-ufraw - a dcraw rwapper with color profile
> >         Nkx_D60_5_2697_00_002_468.icm that ViewNX created when
> >         converting a picture
> > 
> > The sad news for me is that what looks best is ViewNX - Nikons own
> > windows only tool (might work under wine but that's not the point)
> > When using ViewNX it does create a .icm file for many of the pictures. I
> > suspect it is some kind of built in profile that dcraw doesn't read/use.
> > The only real option I currently have is to use the embedded thumbnail
> > which is large pixel wise but low quality.
> > 
> > Is there any suggestions on how I can do the raw conversion with open
> > source tools without loosing so much quality or having to manually
> > fiddle around with every picture?
> > 
> > 
> > /ps
> > 
> > _______________________________________________
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> > Linux [ at ] lists [ dot ] oclug [ dot ] on [ dot ] ca
> > http://oclug.on.ca/mailman/listinfo/linux
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	slainte mhath, RGB

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