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Re: [OM] Sensor Tails . . . [was IMG: October]

Subject: Re: [OM] Sensor Tails . . . [was IMG: October]
From: Mike Gordon via olympus <olympus@xxxxxxxxxxxxxxxxx>
Date: Tue, 7 Nov 2017 19:23:12 -0500
Cc: usher99@xxxxxxx
Kudos to Maestro Moose for such an elegant analysis and the lengths he went to 
perform such an experiment.  Can't say I fully understand the results, but 
probably his method  is the best way to test.  

Such "older" sensors such as on the E-1 were noted for color accuracy and some 
other  pleasant rendering features but it is more difficult to quantify 
objectively than one would think. 
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 and is independent of the 
converter.  Sonnie tends to do well here with a denser CFA but truth  be told 
the measure is noisy
above 80 and not very good at discriminating the sensors.  Purples and true 
violets are notoriously difficult.   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.  
Portra 160 had no trouble with a good scan.  Admittedly I may not be practiced 
enough with the HSL features, but I could not get it right in PS if I stood on 
my head with the ACR conversion. 

I don't understand the colorspace finding as usually found going from raw/tiff 
16 bit to 8 bit jpeg in srgb an issue.  I had an action from an FM'er to 
prevent clipping but the aRGB processed  always looked a bit washed out after 
conversion.
like with the E-M5II in the Moose example.  No clue why that doesn't occur with 
the e-1.  Smugmug does not support tiffs or aRGB so I I abandoned trying to 
establish an aRGB gamut  workflow though I would prefer to keep the files 16 
bit with a wider gamut. 
I don't member precisely what Zone-10 supports now but I  believe supports at 
least the wider gamut. As long as the image is going to be crammed into 256 
flavors of each color it just seemed easier to keep things in sRGB like Chuck 
recommended years ago not long after I joined the list.  I hope to be able to 
change that workflow some day.

Mike
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