<<<<The sensitivity metamerism index (SMI) is defined in the ISO standard 17321
and
<<<describes the ability of a camera to reproduce accurate colors.
<<<The SMI varies depending on the illuminant
-------------Sure, green light and all bets are off.
<<<<and is independent of the converter.
I don't understand. Esp. with Bayer array, there are no colors, just three
incomplete monochrome matrices, until after demosaicing. The converter creates
the RGB colors. It could be argued that a Foveon or an HD Oly image has colors,
but .
Restricted gamut Mike responds----Yes there are layers of complexities.
"Luther-_Ives conditions" where the sensor can distinguish colors exactly as
the human eye are met if and only if the spectral responses of the sensor can
be obtained by a linear combination of the eye cone responses--almost never are
met.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4299059/figure/f1-sensors-14-23205/
---------Is that how they get away with financial shenanigans, a denser
Certified Financial Analyst? Seriously, what's CFA in this context?
The pattern and density of the colored filter array (CFA) matters a bunch in
color accuracy. There are always trade offs. Canyon typically has less dense
array to improve higher ISO performance and sacrifice a tad in color
rendering--they are adept in hiding it with software.
Other patterns than Bayer can be more accurate but have other drawbacks.
http://www.ericfossum.com/Publications/Papers/2015%20JOSAA%20Color%20Filters.pdf
The calculated SMI in these should be pretty good and the RBGCY arrangement
should indeed be more accurate. One suspects like Fuji, it would require a
larger chroma smoothing radius--leading to complexities in conversion w/o
artifacts.
Fovean sensors early on seemed to do OK despite the color problem for a foveon
style sensor - the multi-layer absorbance spectrums are much more different
from the human eye cone sensitivity spectrum than the Bayer filter pass
spectrum is.
**********I wonder about the high res mode with the pixel shift of the
e-m5-II--should be much more accurate. yes???????
---------If it doesn't work, what's the point? I can see gainfully employed
scientists playing with it. I can't see why anyone else would pay much
attention.
Yes---Disappointing in practice. Surely there is something better than Shirley
cards!
https://www.npr.org/2014/11/13/363517842/for-decades-kodak-s-shirley-cards-set-photography-s-skin-tone-standard
Oddly with OM5DII files I found taking Marnie with true violet in the image
worked much better with DXO conversion then ACR in being able to portray the
true violet with accurate skin tones.
_____Again, how can the ISO standard test be independent of converter??
Yes, too many interacting variables and I was surprised-- which is why I
mentioned it.. Conversion with chosen profile, color space, browser and
calibration or lack thereof of the monitor all effect what the final result is.
My monitor is calibrated but very imperfectly.
I would strongly prefer to keep things 16 bit in a wider gamut and store tiffs
or something else. I couldn't in a timely manner figure out a workflow like
yours and stuck with sRGB for now.
Restricted gamut but fewer headaches, Mike
--
_________________________________________________________________
Options: http://lists.thomasclausen.net/mailman/listinfo/olympus
Archives: http://lists.thomasclausen.net/mailman/private/olympus/
Themed Olympus Photo Exhibition: http://www.tope.nl/
|