Zone Placement

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• 09-08-2011, 07:40 AM
Stephen Benskin
As to the difference in spacing of Zones along in the two examples. Everyone should be familiar with the exponential scale of exposure:

For a seven stop scene:
1, 2, 4, 8, 16, 32, 64, 128 for a ratio of 1:128

Add one stop (unit) of flare and it becomes:

2, 3, 5, 9, 17, 33, 65, 129 for a ratio of 1:64 (six stops)

Even though the original scene is 7 stops, you are only dealing with 6 on the film curve. What are the implications of this?

Processing normal for a seven stop scene is really processing for a 6 stop scene. Without the presence of flare, development would have to be one stop less for normal.

The log-H range on the film curve for a seven stop scene would be 1.80 for a one stop flare factor and not 2.10. That means, the place where you determine the density range of the negative would be one stop (0.30) to the left. You can see this in the two examples. While not perfect since the flare factor in the examples is slightly higher than a stop, the density range for Zone I to Zone VIII in Curve B (flare example) is the same as the density range for Zone I to Zone VII in Curve A (no flare example).

The two examples only differ in the interpretation of the information. So, in a shooting situation, there would be no difference in the negatives as they will be subject to the exact same conditions. The question becomes, which one reflects the way it works in the real world and which one is using the same set of conditions and coming out with the wrong interpretation / answer?

The two curves are an example of the importance of correct interpretation of the data.
• 09-08-2011, 08:36 AM
markbarendt
Quote:

Originally Posted by Stephen Benskin
You'd think that something that has been around for over 70 years would have been better defined by now. In sensitometry, 0.30 is always a stop.

Agreed.

Quote:

Originally Posted by Stephen Benskin
With Zones, I see it as a change from one Zone to the next with the original subject is one stop. There has to be a unit of measurement or else it's just gibberish.

Not agreed. Well not agreed that there needs to be a global standard.

The zone system is an artistic ruler.

Zones were specifically designed to translate various and sundry personally defined (artistically chosen) SBRs into a single chosen target paper's range.

We each define how much of a given scene is important. Whatever that SBR is gets hacked up into the zones. The zones may be 1-stop or 0.7 stops wide or 1.2 stops or whatever.
• 09-08-2011, 11:00 AM
Stephen Benskin
Sounds more like a religion to me. Sorry that was flip. I was being flip with Kirk too. Basically, if there's no precision in a language, how can ideas be properly communicated?

According to Zone System testing, Zone I is four stops down from Zone V and Zone VIII is three stops up from Zone V. Sounds to me like the the Zones in the 7 stop range between Zone I and Zone VIII are divided into one stop steps.

And who ever said sensitometry isn't creative? The Zone System is basically simple sensitometry (which includes Tone Reproduction Theory). Perhaps it's more accurate to say the Zone System uses Tone Reproduction Theory.
• 09-08-2011, 11:32 AM
DREW WILEY
OK, I see the game you are playing. The graphs show up poorly on my screen. But my general position is
the same. The Zone System is only what you want it to be, unless you think Minor White or Ansel A. were Moses and wrote the rules on stone tablets. You can think of the dynamic range of films subsisting
between Zones II and VIII or III and VII, or 0 to XII. I just depends on the variables. If you "standardize"
on a film with a modest straight line section, then adapt you model to one with a long straight line, you
either change your vocabulary or break your own rules. And real world exposures rarely correspond to
what happens with a step tablet.
• 09-08-2011, 12:25 PM
Stephen Benskin
And man never walked on the moon. You don't have to come up a conspiracy story. Just read some material on Tone Reproduction Theory. The specific purpose of Tone Reproduction Theory is to model how the photographic process works. Claiming that science doesn't reflect the real world is just an absurd argument.

If you are going to accuse someone of something, bring up specifics, make an argument, so that we can discuss the issue. You're not claiming that flare doesn't exist, are you?
• 09-08-2011, 12:26 PM
joh
ahh...now I understand what the graph's show and what you mean.
It's very interesting...i get a little bit stuck with the translation of
the word flare in this case :)
I never tried a "pre-exposure" but I see that it could realy be worth a mint,
espacially in scenes with high contrast and a 135mm camera.
Thanks for that tip.
• 09-08-2011, 12:51 PM
Where the zones are
In response to your questions: Are the zones on the negative? Are they on the paper? Are they in the scene? The answer is yes to all three. The 'zones' in the subject represent the subject's luminance range, in the negative they are represented by the varying densities from somewhere above Film Base + Fog to the maximum density of the film (D-Max), and same for the paper. The goal is to carry the subject luminance through to the paper, allowing of course for artistic interpretation.
• 09-08-2011, 12:54 PM
RPC
There seems to be some confusion here on what a zone is. In Ansel Adam's Zone System, the term "zone" is used only when referring to film exposure. When referring to negative densities or print densities, he uses the term "values", not zones. Adams says that zones are one stop (an exact doubling or halving of exposure, or change of .3 subject reflection density units) apart. His system is based around this central idea. "Values" can be any distance apart based on many factors.

Quote:

Originally Posted by Stephen Benskin
In sensitometry, 0.30 is always a stop.

In sensitometry, a change of .3 density units on a negative is a doubling or halving of density, but I don't believe I have ever heard this use correspond to the term "stop". I believe a stop refers only to a doubling or halving of exposure, not a doubling or halving of film density.
• 09-08-2011, 01:05 PM
Stephen Benskin
Quote:

Originally Posted by RPC
In sensitometry, a change of .3 density units on a negative is a doubling or halving of density, but I don't believe I have ever heard this use correspond to the term "stop". I believe a stop refers only to a doubling or halving of exposure, not a doubling or halving of film density.

It's common usage.
• 09-08-2011, 01:14 PM
markbarendt
Quote:

Originally Posted by Stephen Benskin
Sounds more like a religion to me. Sorry that was flip. I was being flip with Kirk too. Basically, if there's no precision in a language, how can ideas be properly communicated?

Nope, no religion. :laugh:

Math and physics are precise, art and language are not.

Quote:

Originally Posted by Stephen Benskin
According to Zone System testing, Zone I is four stops down from Zone V and Zone VIII is three stops up from Zone V. Sounds to me like the the Zones in the 7 stop range between Zone I and Zone VIII are divided into one stop steps.

If there is no difference between a zone and a stop, then there is no reason to use the word zone. If you want to talk with precision just stop using the word zone.

I've actually tried to reconcile that in my head and the explanation that fits is that in a standard contrast scene that spacing is true. The imprecision of language makes this idea a challenge to communicate.

If we use +2 development (to keep the math simple) it's only a 5-stop range (not 7) and zone V is not 4-stops up from zone I, it's only 3 stops up measured using a light meter. In this case Zone VIII is only 2-stops up from zone 5, not 3.

Quote:

Originally Posted by Stephen Benskin
And who ever said sensitometry isn't creative?

Not me.
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