Almost nobody uses the Zone System the way it was originally defined for sheet film. It is a stretch to attempt to apply the original Zone System to roll film or to color or digital imaging.

However, as a common frame of reference a particular part of the Zone System is very useful. We can refer to the scale (0, I, II ... VIII, IX, X) used to define the tones in an image or print with Zone 0 representing maximum black, Zone X as maximum white and Zone V as being right in the middle.

That does not mean we are actually "using" the Zone System, just a particular part of it that is actually common to all images and prints - even to painting, tapestry and other forms of two-dimensional art.

Anyone who has worked with film and sensitometry is following the work of Hurter and Driffield whether they use the same methods or tools that were used originally to plot film curves.

Even the statement attributed to Newton (1643-1727), "If I have seen further it is by standing on the shoulders of giants" is a good example since the sentiment can actually be traced back to the twelfth century and probably goes back much further.

If you read what Adams wrote about how he determined the exposure you will see that he knew very well how well the foreground and everything else was going to record.

The way he developed the negative was part of his plan to control the overall contrast. That's what the Zone System is all about - to mate the exposure with the appropriate development.

What is just as interesting is how he changed the appearance of the final print over several decades. His later prints ended up darker and with more contrast while still using the same developed negative.

Almost nobody uses the Zone System the way it was originally defined for sheet film. It is a stretch to attempt to apply the original Zone System to roll film or to color or digital imaging.

However, as a common frame of reference a particular part of the Zone System is very useful. We can refer to the scale (0, I, II ... VIII, IX, X) used to define the tones in an image or print with Zone 0 representing maximum black, Zone X as maximum white and Zone V as being right in the middle.

That does not mean we are actually "using" the Zone System, just a particular part of it that is actually common to all images and prints - even to painting, tapestry and other forms of two-dimensional art.

Anyone who has worked with film and sensitometry is following the work of Hurter and Driffield whether they use the same methods or tools that were used originally to plot film curves.

Even the statement attributed to Newton (1643-1727), "If I have seen further it is by standing on the shoulders of giants" is a good example since the sentiment can actually be traced back to the twelfth century and probably goes back much further.

This is the narrative in his own words:

"I was at a loss with the subject luminance values, and I confess I was thinking about bracketing several exposures, when I suddenly realized that I knew the luminance of the moon—250 c/ft2. Using the Exposure Formula, I placed this luminance on Zone VII; 60 c/ft2 therefore fell on Zone V, and the exposure with the filter factor o 3x was about 1 second at f/32 with ASA 64 film. I had no idea what the value of the foreground was, but I hoped it barely fell within the exposure scale. Not wanting to take chances, I indicated a water-bath development for the negative."

The operative phrase is "suddenly I realized that I knew the luminance of the moon. . . " which implies he abandoned his Plan A to use the bracketing he was considering, and decided on Plan B, to use the luminance to establish the exposure he wanted.

His thought about a second exposure had nothing to do with bracketing either - he just wanted a duplicate of the first. Again, in his own words:

"Realizing as I released the shutter that I had an unusual photograph which deserved a duplicate negative, I swiftly reversed the film holder, but as I pulled the darkslide the sunlight passed from the white crosses; I was a few seconds too late!”

http://anseladams.com/ansel-adams-anecdotes/

So although I generally agree with you, this time I can't on either statement.

And this is an indication that he wanted to bracketed the exposure? It was an afterthought that came to him once the negative was developed and dried.

But you are right - the thought certainly did cross his mind.

Here it is in full context:

https://books.google.com/books?id=I5iyf8kmlHQC&pg=PA70&lpg=PA70&dq=The+white+crosses+were+on+the+edge+of+sunlight+and+reasonably+%22safe%22;+the+shaded+foreground+was+of+very+low+value.+Had+I+known+how+low+it+was+I+would+have+given+at+least+50+percent+more+exposure+(a+half+zone).+I+could+then+have+controlled+the+value+of+the+moon+in+development,+and+the+foreground+would+have+a+slight+-+but+rewarding+-+increase+of+density&source=bl&ots=60-55jcHgn&sig=CbVVdzoFI6HKW-XXcYsbwPRlNDM&hl=en&sa=X&ved=0ahUKEwj_nsOco8_bAhUo4oMKHfQHDhIQ6AEIKTAA#v=onepage&q&f=false