[Leica] Some home science experiments with the M8

[davison_m at msn.com (MARK DAVISON)]

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