Why is Zone System EI often about half rated ISO/ASA?

DREW WILEY · Aug 19, 2015

Gosh. I go out of my way to tangle with tricky and extreme lighting situations. With the cost of 8x10 film, it stings when the lighting
suddenly changes during the shot. But playing cat and mouse with shifting clouds and intricate shadow patterns is a game I absolutely love.
Having the right film along for such conditions certainly helps. And I've done my homework in advance. But ultimately, everything is related
to how you print also - what paper, developer, intended look. The Zone System is just another potential tool in your mental tool box. It's
ridiculous to make a religion out of it, or try to quantify everything. I use it more as a common denominator communication tool, like on these forums, than in relation personal shooting. What I really do, I suspect, is almost instantly visualize the placement of the shadow, mid, and highlight readings on the actual curve of any film I happen to be using, based on lots of prior experience. This happens almost subconsciously, spontaneously, and I rarely goof unless the light does suddenly change. So in that respect, dividing the world into artificially segmented "Zones" would actually be a step backwards. However, learning the Zone System did help back when I was just starting out.

Stephen Benskin · Aug 19, 2015

DREW WILEY said:
Gosh. I go out of my way to tangle with tricky and extreme lighting situations. With the cost of 8x10 film, it stings when the lighting
suddenly changes during the shot. But playing cat and mouse with shifting clouds and intricate shadow patterns is a game I absolutely love.
Having the right film along for such conditions certainly helps. And I've done my homework in advance. But ultimately, everything is related
to how you print also - what paper, developer, intended look. The Zone System is just another potential tool in your mental tool box. It's
ridiculous to make a religion out of it, or try to quantify everything. I use it more as a common denominator communication tool, like on these forums, than in relation personal shooting. What I really do, I suspect, is almost instantly visualize the placement of the shadow, mid, and highlight readings on the actual curve of any film I happen to be using, based on lots of prior experience. This happens almost subconsciously, spontaneously, and I rarely goof unless the light does suddenly change. So in that respect, dividing the world into artificially segmented "Zones" would actually be a step backwards. However, learning the Zone System did help back when I was just starting out.

I agree people shouldn't blindly follow anything. That's what this thread is about. Not religion but iconoclasm It is about determining the validity of a claim that has almost universal acceptance, and proving it isn't valid to compare ZS EIs to ISO speeds. I'm happy you're content with you're personal process, but it's a bit of a non sequitur in this thread.

DREW WILEY · Aug 19, 2015

No it's not, because you're assuming an absolute end-point exists. That wasn't realistic even back when graded papers were dominant. If the Zone System isn't matched to the printing application, it's meaningless. And there never is a fixed endpoint. It's an entirely subjective tool which one bends to one's own needs. ISO/ASA is itself just a starting point, a clue where to begin. Otherwise, trying to quantify the Zone System is largely gentleman's play unrelated to the real world. It's not that precise an exposure model, and never will be. Saying Zone such-and-such must equal a certain density in the negative is silly. It all depends on the film and what you are trying to accomplish aesthetically, not to mention variables such as staining or tanning developers. People make this stuff vastly more complicated than it needs to be; and I state that as a VERY nitpicky printer!

Stephen Benskin · Aug 19, 2015

DREW WILEY said:
No it's not, because you're assuming an absolute end-point exists. That wasn't realistic even back when graded papers were dominant. If the Zone System isn't matched to the printing application, it's meaningless. And there never is a fixed endpoint. It's an entirely subjective tool which one bends to one's own needs. ISO/ASA is itself just a starting point, a clue where to begin. Otherwise, trying to quantify the Zone System is largely gentleman's play unrelated to the real world. It's not that precise an exposure model, and never will be. Saying Zone such-and-such must equal a certain density in the negative is silly. It all depends on the film and what you are trying to accomplish aesthetically, not to mention variables such as staining or tanning developers. People make this stuff vastly more complicated than it needs to be; and I state that as a VERY nitpicky printer!

Wow you have really misunderstood what I'm saying.

DREW WILEY · Aug 19, 2015

Perhaps. If so, I apologize. I'd have to backtrack quite a bit to see the underlying premise, what particular rendition of the ZS you were responding to. Long thread. Maybe we're actually agreeing about all this, but stating it in a different manner.

Stephen Benskin · Aug 19, 2015

DREW WILEY said:
Perhaps. If so, I apologize. I'd have to backtrack quite a bit to see the underlying premise, what particular rendition of the ZS you were responding to. Long thread. Maybe we're actually agreeing about all this, but stating it in a different manner.

I'm not advocating any technique. I'm not telling anybody how to expose, test, or process their film. All I'm doing in this thread is evaluating why the Zone System speed testing method overwhelmingly results in EIs 1/2 to 1 stop slower than ISO speeds. I use sensitometric principles and tone reproduction theory as an analysis tool, but I'm in no way suggesting that anyone should do sensitometric testing. By using these tools; however, I am able to breakdown the different methodologies and determine their differences. I'm not saying one system results in better images than another. Just that people who use Zone System testing may be misinterpreting the results.

The ZS / ISO discrepancy began over 50 years ago with the introduction of the 1960 ASA B&W film standard. Over the last 50 years how many Zone System practitioners have claimed that the Zone System is the true film speed and that there exists a conspiracy between manufacturers and ISO speeds vs the Zone System and ISO Standard use two different methodologies? I'm saying they are two different methodologies and all things being equal will produce different speed values. If it's that simple, why all the conspiracy theories all these years? People who only understood the Zone System didn't have the theoretical tools necessary to evaluate the two methodologies.

What to take away from the analysis is up to the individual. My intention is to broaden awareness that the tools to an increased understanding of the photographic process are out there if someone wants them. Many people are unaware anything exists outside of the Zone System simply because that's all they've been exposed to. That's one of the reasons why, with Bill Burk's help, I posted online some key papers on photography. Nothing by Jones though because those are too long.

Stephen Benskin · Aug 19, 2015

This is from page 55 of Adams' The Negative.

Bill Burk · Aug 19, 2015

I think about Zone System (or any metering method including ISO/ASA) as an overlay to the film's sensitometric curves.

Once I draw up my curves, the drawing never needs to be changed (unless I change developer) because the graph reflects the characteristics of the film.

It's like a topographic map of the mountains. I might draw trails and parking lots on a topo map to update the map or draw where I've been or plan where I want to go. But I don't feel any need to change the contour lines. Those mountains are just there.

So I imagine, Drew Wiley, you have no problem envisioning where your pictures will fall on the film's characteristic curves, just as I bet you can tell exactly what lies ahead on the trail by looking at a topo map.

Stephen Benskin · Aug 20, 2015

Bill Burk said:
I think about Zone System (or any metering method including ISO/ASA) as an overlay to the film's sensitometric curves.

Once I draw up my curves, the drawing never needs to be changed (unless I change developer) because the graph reflects the characteristics of the film.

Exactly. Curves don't say much by themselves. The diagnostic strength of the tone reproduction diagram comes from its ability to overlay different exposure situations onto film and paper curves.

markbarendt · Aug 20, 2015

What I don't get, is if they weren't going to use the industry's standard; why didn't or don't the zone system adherents simply use an EI that gives them the camera setting directly from the normal zone they want to peg?

If Zone III (or 0.1 or whatever) is what you/they want set exposure by, why not use an EI that just gives them the camera setting?

Ian Grant · Aug 20, 2015

markbarendt said:
What I don't get, is if they weren't going to use the industry's standard; why didn't or don't the zone system adherents simply use an EI that gives them the camera setting directly from the normal zone they want to peg?

If Zone III (or 0.1 or whatever) is what you/they want set exposure by, why not use an EI that just gives them the camera setting?

Using the Zone system and BTZ means you measure the extremes, highlights and shadows and make adjustments to the Development N+1, N+2, or N-1, N-2 etc if necessary that, affects the EI slightly, a higher EI when you increase development and a lower EI when you reduce it.

In practice some of us will quickly check the extremes and meter from a specific zone when processing is normal, so at our ore-determined EI.

Ian

Xmas · Aug 20, 2015

If you are stuck with 36 frames or even 10.
Then you don't need to worry about contrast or n+-x.
All you need to do is spot a shadow for negative or a highlight for transparency.
And you need to know what EI to use and if you need to margin it.
If it is a critical shot you bracket the margins.
If it is a 16x20 camera it is different.

Stephen Benskin · Aug 21, 2015

markbarendt said:
What I don't get, is if they weren't going to use the industry's standard; why didn't or don't the zone system adherents simply use an EI that gives them the camera setting directly from the normal zone they want to peg?

If Zone III (or 0.1 or whatever) is what you/they want set exposure by, why not use an EI that just gives them the camera setting?

Mark, I've been giving your idea some thought. It's probably a valid approach only if you limit your metering to just keying off the chosen Zone. You would be sacrificing the ability or making it difficult to evaluate the luminance range. According to Connelly in Calibration Levels of Films and Exposure Devices, "The validity of the exposure determination method must, therefore, depend upon the acceptability of the resulting photographs which are produced by substituting a single value of luminance in the determination of exposure to represent the multiplicity of value of luminance of the scene itself."

In other words, place and fall. Even if a person "exposes for the shadows," they are actually choosing a mid-tone exposure that allows the important shadow exposure to fall around the Zone they desire. I think that adjusting the EI for keying exposure would limit the analytical aspects of the place and fall method.

markbarendt · Aug 21, 2015

Ian Grant said:
Using the Zone system and BTZ means you measure the extremes, highlights and shadows and make adjustments to the Development N+1, N+2, or N-1, N-2 etc if necessary that, affects the EI slightly, a higher EI when you increase development and a lower EI when you reduce it.

In practice some of us will quickly check the extremes and meter from a specific zone when processing is normal, so at our ore-determined EI.

Ian

Metering other zones to peg the shot is a great example.

I understand the usage, even use zoning as you suggest just for fun on occasion.

I used to do a fair amount of sporting event photography where the participants would follow a course that led each participant through 2 or 4 light changes of as much as 5-stops in about 30 seconds as they passed my position. (Kayaks moving through a race course full sun on whitewater to deep deep shade on dark dark green water and everything in between.) The problem was compounded by the reflectivity of the subjects boats and gear, some in bright yellow others all in black...

In this situation I'd pick targets in the scenes before the event and offset the EI on the camera meter to calibrate to those targets and to peg the exposures without any math. Meter the target, exposure lock button, reframe, focus button, shoot, repeat for next scene. It depended very much on zoning principles and was very fast and with a camera like an F100 or better, easy.

In zoning measuring high and low for contrast is just a matter of counting EV stops. The EI setting doesn't matter there as long as it's within the meter's range.

Seems to me that though, that as a baseline, it might be easier for those in the zoning world to design their regular EI to use the zone they prefer to set the camera by.

markbarendt · Aug 21, 2015

Stephen Benskin said:
In other words, place and fall. Even if a person "exposes for the shadows," they are actually choosing a mid-tone exposure that allows the important shadow exposure to fall around the Zone they desire. I think that adjusting the EI for keying exposure would limit the analytical aspects of the place and fall method.

Stephen you statement is actually demonstrating the complexity that I'm suggesting could be removed.

Just meter the shadow using an EI that gives you the camera setting, done.

We place one point and the rest fall. It doesn't matter which point we start with.

So why not skip the mental backflip of doing a "conversion to the mid-tone" to find the camera setting for the baseline.

(BTW I know I have no hope of unseating the status quo, it is too well ingrained. I'm not trying to change Ian's, Bill's or Drew's practice. It's just a thought.)

Xmas · Aug 21, 2015

Well I set my Weston or OM4 ISO offset from datasheet ISO 4/3 of a stop.

The Weston calculator has a zone 1 datum for zone 1 metering the OM4 a shadow button...

When I'm shooting street I measure shadows both sides of street...

If it is a still life I bracket.

There is a paper sticker for the Weston calculator if you don't count...

Stephen Benskin · Aug 21, 2015

markbarendt said:
Stephen you statement is actually demonstrating the complexity that I'm suggesting could be removed.

Just meter the shadow using an EI that gives you the camera setting, done.

We place one point and the rest fall. It doesn't matter which point we start with.

So why not skip the mental backflip of doing a "conversion to the mid-tone" to find the camera setting for the baseline.

(BTW I know I have no hope of unseating the status quo, it is too well ingrained. I'm not trying to change Ian's, Bill's or Drew's practice. It's just a thought.)

Didn't Picker have something similar but with keying the highlights. Expose for the highlights and let the shadows take care of themselves. Any method will work well enough in the majority of cases. Which is why there are so many different methods.

RobC · Aug 21, 2015

using a spot meter requires making a judgement about what you want where. It is far easier to make a judgement about which highlight you want to just retain full textural in such as a brides dress or a shadow you just want to retain full textural detail in such as a grooms suit than it is to make a judgement about which tone is a zone V. So it makes sense to key to one end or the other of the scale and personally I think its better to key to a highlight providing you know that you are not losing shadow detail that you want to keep.

don't incident meters key to highlights?

Xmas · Aug 21, 2015

If you are doing reversal film you need to key to highlights?

RobC · Aug 21, 2015

Michael R 1974 said:
Never understood the point of systems using highlights to key exposure, in the context of current materials. Actually this seems to be a general problem with systems - ie they are all way too damn old.

Well if you use an incident meter then you are keying to whatever the incident meter is keyed to which is what? And if you vary anything such as EI then you are implementing your own system which is keyed to what.

If you are using a spot meter you aren't keyed to anything but it is helpful to know what setting to use so you need to know how to use it and make a judgement so again you are keying to your own system whatever that might be.

If you use in camera meter then you are keying to that whatever that uses.

So you are always using a system even if you don't know it and most people seem to agree that using an incident or spot meter allows you to be consistent about it whether you key to shadow or highlight. I doubt anyone could be consistent trying to key to a midtone, it would be very easy to be a stop or more out unless you use a reference tone like a kodak grey card but that's keying to something as well.

DREW WILEY · Aug 21, 2015

I often go back and forth between color and black and white shots. With color, it's really the hues you most want to protect with correct saturation that count, so I find the ZS largely meaningless for color photography (despite AA's attempt to apply it). With high-contrast B&W
scenes I might meter shadow, highlight, and often midtones too. The Pentax Spotmeter makes that kind of thing easy. But it's really the
shadow values that are most important, since nothing will be there if you underexpose, and you can't recover something that's not there to
begin with (even though digital printers seem to think they can walk on water, though they actually trip over their own shoelaces). More often I know how a film will handle under a given situation, so take a single critical reading. But that's due to experience. Any new film I test first. Gray cards? Ha! I test those too. There is a lot of variation in them, even from the same brand.

markbarendt · Aug 21, 2015

Stephen Benskin said:
Didn't Picker have something similar but with keying the highlights. Expose for the highlights and let the shadows take care of themselves. Any method will work well enough in the majority of cases. Which is why there are so many different methods.

Exactly.

RobC said:
don't incident meters key to highlights?

No. Incident meters don't "see" the scene. They measure the light falling on the scene.

They can be forced to key off different light sources by retracting the dome and/or pointing the head in a different direction. This is typically used when duplexing or when setting up artificial lighting.

Michael R 1974 said:
... in the context of current materials. Actually this seems to be a general problem with systems - ie they are all way too damn old.

Yep.

markbarendt · Aug 21, 2015

RobC said:
I doubt anyone could be consistent trying to key to a midtone, it would be very easy to be a stop or more out unless you use a reference tone like a kodak grey card but that's keying to something as well.

There are lots of reference mid-tones that are very reliable to use as a key. Roadways, grass, clear blue northern sky, the back of my hand, jeans...

RobC · Aug 21, 2015

markbarendt said:
No. Incident meters don't "see" the scene. They measure the light falling on the scene.

They can be forced to key off different light sources by retracting the dome and/or pointing the head in a different direction. This is typically used when duplexing or when setting up artificial lighting.

BUT having measured the light falling on the scene which is a measurement in Lux or lamberts or whatever, they MUST do something with it to convert it to an aperture and/or shutter speed for you to set your camera to. They do this by taking your input parameters which are film speed plus aperture or speed and then spit out a result. That result is based on programmed keying to somewhere on the exposure curve using some standard which is based probably on or close to the ISO film speed curve calculations lux exposure.

So you are wrong to say an incident meter just measures the light. Yes it does but it also tells you how to use that based on its "keying" algorithyms. It doesn't give you the results in lux or lamberts which is what you implied by saying "they measure the light falling on the scene", it does calculations based on that.

RobC · Aug 21, 2015

markbarendt said:
There are lots of reference mid-tones that are very reliable to use as a key. Roadways, grass, clear blue northern sky, the back of my hand, jeans...

And they all vary greatly in luminance according to age, wet or dry or tarmac or concrete, type grass, how wet or dry it is, atmospheric conditions and altitude, whether you've got a suntan or are pasty looking and/or jaundiced, and how faded your jeans are.

Some really good references there.

You are using your experience which others may not have.

p.s. If your system works for you then it works for you and my system works for me and the next persons system works for them then it only goes to show that there's a 1001 ways to skin a cat.

And that in short means follow your nose and tread your own path and you'll probably get there which in turn means you can pretty much ignore anything anyone here tries to insist is the right way to do it.

Why is Zone System EI often about half rated ISO/ASA?

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