And the problem with that is.....? I wasn't saying that the concept of unity gain ISO isn't important. But there are a lot of things that get studied in a lab that have little to no practical application (at least at this time). Most of us aren't lab rats; however. Most of us are 'in the field' photographers so it makes complete sense to understand how a given lab or theoretical test plays out in practical use. As has been laid out over the course of this discussion there are, definitely, practical implications. And the findings that Jim has laid out and explained are consistent with other, considered reliable, sources which simply lends increased credibility to both. There's also something to be said for being able to explain a technical or theoretical construct and make it more widely understood. Some are unable to do that because they don't really understand the underlying technicalities themselves. Others won't do that because they think it gives them some measure of superiority over others, it makes them feel elite or special.
My response was to your earlier post:
What is the purpose of knowing the Unity Gain ISO? What practical purpose does it have? Similarly what practical purpose does knowing the full well capacity have? Are we able to use the information to determine exposure on the fly, in the field?
The problem with that, if you must know, is:
A gentleman puts a lot of research and work into a post - which he publishes on what I thought was a forum where there is at least some slight interest in matters technical. Your quote immediately above decries the usefulness of the OP with a series of demeaning rhetorical questions. Your post offered nothing other than the negative implication that the OP is of no practical use. Effectively thereby, it dismissed the OP as useless.
The "Real World" card was played in the last line " . . to determine exposure on the fly, in the field . . "
Perhaps the problem wasn't what
was said, it was how
it was said. And, I must confess to a certain sensitivity in the area of this topic. I once calculated the saturation-based "native" ISO of a Sigma DSLR sensor, posted it with formulae and quotes from the ISO standard on a Sigma forum, thinking it might be of interest, and was promptly beaten up for being too technical.