Re: [UFRaw-Devel] New curve format in Nikon NEF files?

[Omari S. <xs...@cs...>]

Niels Kristian Bech Jensen wrote:
>> Date: Thu, 18 Dec 2008 10:12:29 -0600
>> From: udi...@gm...
>> To: ufr...@li...
>> Subject: Re: [UFRaw-Devel] New curve format in Nikon NEF files?
>>
>>> When loading NEF files from newer Nikon cameras I often see underexposure on the magnitude of around 2 EV compared to the embedded thumbnail image. I have seen this behaviour with files from Nikon D3, D3X, D300, D700 and D90. UFRaw shows the curvesize (in Options -> Log) as 578 bytes for all these NEF files.
>> With one D90 photo I tested, I got results very similar to the
>> embedded image by setting exposure to +1EV and linearity 0.05.
>>
> That gives us two ways of getting results similar to the embedded image:
> 
> 1. Use the color profile from Capture NX with no exposure compensation.
I've been using the D300 profile ([1]) from the CrushedRedPepper blog ([2]) for 
a couple months now, and since I started using it, the UFRaw exposures have been 
dead on.  To be clear, I used to run into the underexposed image problem, and 
it'd always vary a bit so that I couldn't just stick with +2EV or something. 
But using this profile, the problem is gone.  See [3], [4], and [5] for 
comparison images when using no profile, the matrix, and the D300 profile, 
respectively.

I have noticed that the profile tends to undersaturate reds in some situations, 
but I imagine I can clean that up when I profile my actual camera rather than 
using a generic profile.  Needless to say, though, this was a lifesaver for me.

Oh; for the Crushed Red Pepper profile, I use settings: gamma 0.45, linearity 
0.01.  I find that this matches my images better than the 0.00 linearity that 
the CRP site suggests

[1] http://blog.crushedredpepper.com/nikon/scripts/Nkx_D300_standard.icm
[2] http://blog.crushedredpepper.com/nikon/raw.html
[3] http://ocaml.xvm.mit.edu/~xsdg/stuff/ufraw/d300/0_no_profile.png
[4] http://ocaml.xvm.mit.edu/~xsdg/stuff/ufraw/d300/1_color_matrix.png
[5] http://ocaml.xvm.mit.edu/~xsdg/stuff/ufraw/d300/2_crp_profile.png

HTH,
--xsdg