Hallöchen!

Ger Siemerink writes:

> Torsten, Well done and it would be nice if you summarize the
> workflow into a blog on darktable.org.

I'm so glad if that file is closed ... ;-)  Really, I'm a
calibration Nazi but colour matrices and fisheye entry pupils are
much more fun!  And, this is tedious reverse engineering of
something the vendors should simply publish.

Speaking of vendors ... I prepared

http://wilson.homeunix.com/basecurve/all_linear.png
http://wilson.homeunix.com/basecurve/all_log.png

> [...]
>
> Maybe stupid thought: how does the type of lens, protection filter
> and automatic WB influence the result.

As far as lens and filter are concerned, it depends on spectral
dependence.  If they just make the image darker as if the shutter
speed was increased, they don't affect the measurement.  Vignetting,
TCA, and distortion impose no problems at all.

WB should be set correctly when shooting for the basecurve.  This is
because the camera applies a colour matrix when generating a RAW,
and we don't know this matrix.  Thus, we cannot undo its effect.
Therefore, we must try to get fully desaturated (aka greyscale) data
into the colour matrix, because then it has no effect.

> I remember a blog saying that the best time to take a picture was
> at noon on a cloudless day.

This has no significance here.  ;)

Tschö,
Torsten.

-- 
Torsten Bronger    Jabber ID: [email protected]
                                  or http://bronger-jmp.appspot.com


------------------------------------------------------------------------------
Get 100% visibility into Java/.NET code with AppDynamics Lite!
It's a free troubleshooting tool designed for production.
Get down to code-level detail for bottlenecks, with <2% overhead. 
Download for free and get started troubleshooting in minutes. 
http://pubads.g.doubleclick.net/gampad/clk?id=48897031&iu=/4140/ostg.clktrk
_______________________________________________
darktable-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/darktable-devel

Reply via email to