[HDRI] calibrating HDR pictures with real world luminance

[Bernhard Vogl]

I'm not a researcher, so pls. take this into account when reading my 
considerations:
>  
> 2) In some references, it is mentionned that I should always capture 
> LDRs with a Daylight white balance.  Is this the general agreement?  
> Even if my scene is lit with tungsten lights?
In my operating experience, it is easier to control color (workflow) - 
even if there are no "outside" image areas.
Though, you can always correct WB in HDRShop (->Pixels->WB selection)
>  
> 3)I found limited explanation on how the camera calibration curve 
> would affect the results in HDR Shop.  I would have to think  that 
> this is to linearize the color values (remove the effect of Gamma + 
> CMOS response) so luminance measurements can be actually applied to 
> the colors later on.
This is also my understanding.
>  
> 4)HDR Shops refers to Fstops in the UI.  However,  I read that you 
> want to maintain Fstops constant and only change the shutter speed.  
> The problem I  have is that the interpreted Fstops of HDR Shop turn 
> into some "arbitrary" numbers and I can't really type-in the values 
> used by my camera.
I personally would be interested to see, how far Photomatix would 
support you with this task:
The new version reads EXIF data, resulting in "normalized" HDR images. 
Basic idea behind is to make tone mapping in a panorama workflow easier, 
but it should also make your task easier reproduceable.
I didn't invest much time to test this functionality, but as far as i 
found out, it turned out to be useful when using panos for IBL (i don't 
have to fiddle that much with exposure correction)...

Best regards
Bernhard

-- 
Bernhard Vogl
Vienna, Austria
http://dativ.at
http://www.austria-360.at
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