I checked the NEF in CaptureNX. The white balance of the NEF was 8000 and
the Max in CaptureNX is 9090.
Antti
On 16 December 2013 23:20, Chris Siebenmann <[email protected]> wrote:
> Thank you! I just pulled the latest git tip and rebuilt, and now my
> sample NEF comes up with a much lower white balance and so on.
>
> - cks
>
> | sorry i was confused, we normalise to D65 daylight, not D50. so i'm
> | now using the first preset with `daylight' or similar in the name, not
> | 5000k. which unfortunately means that 5000k shows up as 5300odd in the
> | gui. not sure i want to special case my way around that, definitely
> | not before 1.4 though. fix pushed.
> |
> | cheers,
> | jo
> |
> | On Tue, Dec 17, 2013 at 9:02 AM, Chris Siebenmann <[email protected]
> >wrote:
> |
> | > I'd say go with the 5000k value(s) in the abscence of better
> information.
> | >
> | > Unfortunately I don't have Nikon's official software (or any
> commercial
> | > software) that could be used to double-check the nominal official WB to
> | > try to match their results. If someone does have Capture NX or
> Lightroom
> | > or etc to check I'd be interested in what the results are.
> | >
> | > (I tried Nikon's free View NX2 software in a Windows VM but I couldn't
> | > get it to report the actual white balance colour temperature. It did
> | > seem to avoid the initial magenta colour bias, though.)
> | >
> | > - cks
> | >
> | > | hm. using 5000k results in your camera wb as ~13000k, using the first
> | > | daylight one results in ~9300k. you get to choose, i don't have to
> work
> | > | with files from that camera..
> | > |
> | > | j.
> | > |
> | > |
> | > | On Tue, Dec 17, 2013 at 8:29 AM, Chris Siebenmann <
> [email protected]
> | > >wrote:
> | > |
> | > | > Somewhere in the Darktable Redmine system I have a couple of
> | > | > contributed white balance coefficients for a range of D7100 white
> | > | > balances (both the presets and a range of absolute K values). I
> think
> | > | > that 5000K should be used as the 5000K normalization point.
> | > | >
> | > | > (If I remember the D7100 manual's discussion of this correctly,
> also
> | > | > reported in the Redmine system, the plain 'daylight' preset is
> close
> | > | > to but not quite on 5000K. So Darktable might as well use the one
> that
> | > | > Nikon claims is exactly 5000K.)
> | > | >
> | > | > - cks
> | > | >
> | > | > | the k values are pretty hacky, so don't shudder reading on..
> | > | > |
> | > | > | these are normalized to daylight wb, which is said to be 5000k.
> the
> | > | > | values live relative to that. so that's somewhat an
> approximation,
> | > | > | and we have to try to get daylight balance from somewhere.
> judging
> | > | > | from a quick look at your raw i don't think we get daylight white
> | > | > | balance values from anywhere, i think we first check the raw
> file,
> | > | > | then the wb presets for something with the name `daylight' and
> then
> | > | > | fall back to something totally idiotic (i'm quite sure that's
> what
> | > | > | happens here). the d7100 seems to have daylight wb presets, but
> with
> | > | > | more esoteric names. which one would you prefer to be used as
> 5000k
> | > | > | reference? daylight fluorescent, white, or 5000k?
> | > | > |
> | > | > | /me tries a few things.
> | > | > |
> | > | > | j.
> | > | > |
> | > | > |
> | > | > | On Tue, Dec 17, 2013 at 8:12 AM, Chris Siebenmann <
> | > [email protected]
> | > | > >wrote:
> | > | > |
> | > | > | > | > It's easiest to explain what I'm seeing with a sample NEF
> and
> | > its
> | > | > | > | > embedded preview:
> | > | > | > | >
> http://www.cs.toronto.edu/~cks/tmp/darktable/DSC_4429.NEF
> | > | > | > | >
> | > | > http://www.cs.toronto.edu/~cks/tmp/darktable/DSC_4429_preview4.jpg
> | > | > | > |
> | > | > | > | Your second link is broken, looks like it should be:
> | > | > | > |
> | > | > | > |
> | > http://www.cs.toronto.edu/~cks/tmp/darktable/DSC_4429-preview4.jpg
> | > | > | >
> | > | > | > Oops, yes. My fault and thanks for letting me know. (I've
> added a
> | > | > | > symlink so that it works now, or at least so that it should.)
> | > | > | >
> | > | > | > | IIRC, it was stated that the temperature control on the white
> | > balance
> | > | > | > | module is for convenience only, and the value is not related
> to
> | > any
> | > | > | > | objective measure... of course, if it's maxing out, that's
> not
> | > very
> | > | > | > | convenient. :)
> | > | > | >
> | > | > | > My view is that getting it into the rigth ballpark is
> important
> | > for
> | > | > | > both adjustability (a 100 kelvin change means more at lower K
> | > values)
> | > | > | > and for understanding what's going on and general usability.
> For
> | > | > | > example, the D7100 '5000K' white balance present currently
> comes
> | > out
> | > | > | > with a DT K value of 8364K and the 'shade' preset to 17199K.
> And
> | > if the
> | > | > | > values are arbitrary and way off, clamping them to 23000K is
> (as
> | > you
> | > | > | > mentioned) not too useful.
> | > | > | >
> | > | > | > (Part of the usability is for adopting processing suggestions
> | > written
> | > | > | > for other RAW processors to Darktable. Right now, 'add 200K of
> | > white
> | > | > | > balance' is not really useful or easily adoptable directions
> for at
> | > | > | > least some cameras.)
> | > | > | >
> | > | > | > In fact I would go so far as to say that if Darktable's Kelvin
> | > scale
> | > | > of
> | > | > | > colour temperature is so arbitrary and so far off the scale
> should
> | > not
> | > | > | > be called '(kelvin) colour temperature'. Call it 'white balance
> | > index'
> | > | > | > and scale it differently using whatever units are convenient.
> | > | > | >
> | > | > | > (Of course I would prefer if DT really had a Kelvin colour
> | > temperature
> | > | > | > scale and it worked right. But clearly it doesn't right now,
> so the
> | > | > | > easiest fix may be some redefinitions. This might also allow
> for
> | > it to
> | > | > | > be in more convenient units for changes.)
> | > | > | >
> | > | > | > - cks
>
>
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