[Leica] Some home science experiments with the M8

[philippe.orlent at pandora.be (Philippe Orlent)]

Fascinating how you go into depth of this.
Thanks for sharing,
Philippe



Op 21-nov-06, om 20:43 heeft MARK DAVISON het volgende geschreven:

> 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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