You keep saying "arbitrarily" selected noise thresholds. It isn't arbitrary. It's very specific.
The Imatest "quality" DR measurements (low/med/medhigh/high) have arbitrarily selected noise floors that someone thought represented "quality" points. That's why there are 4 reported values in addition to total measured DR.
It is the RMS of read noise,
Not what we're talking about. (And for the millionth time, cannot be simply converted into system DR.)
On the other hand...using ACR/LR to perform conversions, when the underlying algorithms used in that product have changed, often considerably, over the years and countless minor version releases, not to mention the fact that the algorithms are black box, leads to highly suspect, and highly arbitrary, results.
Have you shot a step wedge and tried to use NR to make black and white steps gray yet?
Please go try
How is a DXO Screen DR measure any different than a "system" measurement done by IR?
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