[Leica] Some home science experiments with the M8

[harrison at mcclary.net (Harrison McClary)]

Wow Mark...you lost me after "Basically" LOL...

Glad to see there are such scientific minded folks on the LUG.


MARK DAVISON wrote:
> Those of you who like home science experiments might want to look at 
> my latest contribution to the thread:
>
> <http://www.leica-camera-user.com/digital-forum/9637-new-m8-profiles-c1-instructions.html>
>  
>
>
> Basically I've figured out how to get ahold of de-mosaiced raw linear 
> device coordinates from M8 pictures, and I've photographed a physical 
> spectrum from a prism to find the boundary of the device gamut.  Then 
> I've taken some pictures outdoors of some purple balloons whose 
> chromaticity coordinates lie uncomfortably close to those of a black 
> object turned purple under incandescent.
>
> Sure enough when you apply a tweaked profile which is supposed to take 
> out false purple, it makes part of the balloons dark gray.
>
> So you can't distinguish sufficiently well between false purple and 
> true for the tweaked profile to always work.
>
> I think I'll work with my 7th grade son to make a home spectrograph 
> with a diffraction grating, and then perhaps we can calibrated the 
> spectrograph, and I can make a spectral map for the M8 with the 
> wavelengths annotated.  This will allow us to see how the estimate of 
> principal wavelength (the exact physical analog of hue) changes with 
> and without a UV/IR cut filter for various objects.
>
> Mark Davison 


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Harrison McClary
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