zone system question : LUSENET : Large format photography : One Thread

in phil davis' book, "beyond the zone system", he states that the zone system should be used with zone pairs 4 zones apart. for example, zone III and zone VII, zone II and zone VI, etc. is this valid and does anyone agree, disagree, or have a comment regarding the validity of this recommendation. thanks.

-- howard schwartz (, January 17, 2002


I'd been hearing about this book for ages in this forum, and a couple of weeks ago I finally got my hands on a copy.
All I can say is - what's all the fuss about?
The illustrations are uninspiring and of low quality, the information's shallow and adds little to AA's original concept, and the advice about incident light measurement shows a fundamental misunderstanding of it. Have I missed something? Or is there another book of the same name that's far superior?

-- Pete Andrews (, January 18, 2002.


I have to agree that BTZS seems to elevate arcane alchemy to the staus of micro-surgery. Surplus to requirements for all but the boffins.

The one notion that I did find plausible, however, was the incident meter discussion. Not for me, I'm a 1 degree spot addict, but I ran a buddy that can't afford a spot-meter through the technique and he's getting more consistent and better exposed negs than ever before. Not necessarily perfect, just better.

Walter Glover

-- Walter Glover (, January 18, 2002.

I agree that the book is aracane and difficult to read in many areas. I think most of the first half of it could be eliminated without any loss. However, I know Phil Davis reasonably well and I'd be very surprised if he has a "fundamental misunderstanding" about anything related to photography. Of course I've been surprised before, so it wouldn't be the first time. With respect to the question concerning the validity of the "recommendation," it's been quite a while since I read the book but I don't offhand recall a recommendation that zone pairs always be placed four zones apart. As a general rule, there are considered to be five zones in which detail will be seen in a print made from a normally developed negative, Zones III through VII, and these zones are four apart. Are you sure he wasn't just saying somethinglike this, as opposed to "recommending" a placement like this? The whole idea of the zone system is to permit aesthetic judgements about how a scene should look in the print and then to permit you to expose and develop your film to achieve that look, so it would be a little surprising to find someone suggesting that zones should always be four apart as any kind of inflexible rule.

-- Brian Ellis (, January 18, 2002.

Actually I think you are confusing SBR (Subject Brightness Range) and development reccomendations. For example a normal SBR that requires a N develpment has 5 zones. so you can hace ZIII to ZVII if you wish to render the image darker or lighter you can move the zone placement. Now you dont have to have these type of zone separation it can be different ones, is just that what Davis calls a "normal" SBR.

IN the end I found this book and the techniques way more complicated than they should be. THe zone system is only a way comparing and controling exposure and developing and as AA and others explained it is very simple.

-- Jorge Gasteazoro (, January 18, 2002.

The best book I have ever read about the Zone system, is the Zone VI Workshop by Fred Picker, not complicated at all. Pat

-- pat krentz (, January 18, 2002.

Howard, The bigger the difference between the scene brightness or the "zones" you plan to place them on will result in lowering the possibility of picking the wrong development time. Of course, some subjects are very low contrast and you will be forced to use a value less than 4 zones apart. If you are a precision person, there is another alternative to the Zone System. I wrote a series of articles for Photo Techniques magazine that describes the theory and practice. Testing is tedious but using it in the field is as easy as the Zone System and far more precise. Study everything you can, trust your bs meter to keep you on the straight and narrow, and go have fun making images.

-- Andy Eads (, January 18, 2002.

Mr. Schwartz:

Davis recommends that you stay with a a four zone spread because using a larger or smaller zone spread will build into your exposure/development calculations an error in the estimation of the total subject brightness range, which, in turn, will lead to an error in the specified development time. Remember that you are trying to make a negative whose density range will fit perfectly on your chosen type and grade of paper. To make such a negative you must find the right development time. You do that by, in effect, determining the total scene subject brightness range by measuring a portion of it -- the low zone-high zone spread -- and consulting the graph you have made from your test data of subject brightness range vs. development time. In BTZS, 4th ed., at pages 125 to 126, Davis explains how choosing zone pairs with a spread greater or less than 4 can lead to an error in the estimation of the total subject brightness range. In his example two different scenes are measured, one using a a four zone spread and one using a six zone spread. each calculation leads to a development recommendation of N-1. Yet the subject brightness ranges of the two scenes differs by about 2/3rds of a stop. As Davis says, "obviously development that's correct for an 8 & 3/4 stop subject cannot also be optimum for an 8 & 1/6 stop subject . . . ." (Davis goes on to say, "you may or may not consider this to be a significant error because both negatives will undoubtedly be printable.")

The recommendation, therfore, is certainly valid. I think perhaps the question you are really asking is whether the error introduced by picking a zone spread other than four is really worth worrying about. My answer is that if your scene permits you to use a four zone spread why not do so and avoid one possible source of error? On the other hand, not every scene lends itself to 4 zone-spread metering. If I understand what Davis is saying, you should not hesitate to meter and shoot with an alternate zone spread. The error you introduce may mean that your negative will not fit your paper perfectly, but it should certainly be printable.

Remember that Davis's variant of the Zone system, like the original, is meant to aid your photography, not hinder it.

Mr. . . . Andrews, I think it was, says about Davis's book that, "the information's shallow and adds little to AA's original concept . . . " I'm not sure what he means by saying that the information is "shallow." If by "shallow" he means "straightforward" that would seem to me to be a good thing. I want the artistry in my photographs to be "deep" (if at all possible); I am perfectlly happy for the technical stuff to be as shallow as possible. As for the claim that the book "adds little to AA's original concept," I'm sure that, conceptually, this is absolutely true, and that Davis would agree. What BTZS does is to provide a way to minimize certain errors that creep into our exposure/development calculations, like the one mentioned above, and to generate quickly and relatively painlessly, the data necessary to make reliably accurate exposure-development calculations under a wide range of subject brightness conditions. For example, BTZS makes it easy to select the correct film speed for the scene's subject brightness range (remember that as the subject brightness range increases, so that minus development is indicated, exposure must be added to account for the loss of film speed brought about by the curtailed development time). How is this information generated using the more traditional zone system approach? The methods recommended by White, Lorenz, and Zakia in their New Zone System Manual are vastly more complicated and time consuming than Davis's aproach. Of course there are simpler approaches to the film speed problem; a number of my friends seem to use trial and error with a high degree of success. As I have said in earlier postings defending Davis's book, wonderful, technically accomplished photographs are made all the time using the traditional zone system approach, and even the no-system approach. (To take just one example, Jock Sturges makes beautiful large format B&W images, and is said to loathe the very idea of the zone system). But for those for whom a somewhat technical approach is not too daunting, Davis's variant of the zone system works very well.

David Mark

-- David Mark (, January 18, 2002.

The fundamental misunderstanding of incident light metering is illustrated by the recommendation to take a reading next to the brightest part of the subject (where possible) and next to the shaded part of the subject, then equating these two readings to a subject 'luminance' range.
This actually tells you almost nothing about the subject brightness range, and is a complete misuse of an incident meter, which already takes the 7 stop range of a normally developed film into account. The method is more applicable to a simple wide-angle reflected meter, which seems to get almost no mention in the book at all.

My other objection to the book is that it wades straight into 'sensitometry made obtuse' without mentioning the fundamental reason for using it. The underlying principle of the Zone system is, or should be, pre-visualisation. I don't think I saw a word about pre-visualisation in the whole book.

When AA first thought up the zone system, film speeds weren't very standardised, and manufacturers didn't issue comprehensive sensitometry data about their products. He was forced to spend a lot of time characterising the materials he used.
I'm not entirely convinced that such an approach is even valid today; let alone recommending to people that they waste time making a poor densitometer from a perfectly good spotmeter, and THEN recommending that they use an incident lightmeter to take subject brightness range readings.
It's like a DIY book recommending that you use a screwdriver as a chisel, and then knock your screws in with a hammer!

-- Pete Andrews (, January 21, 2002.

People are always trying to make any system better but few succeed. If you understand what the zone system of film exposure and development is telling you about the response of film to development then you need look no further. But people for some reason need to make something that is incredibly simple into something that is hard to understand. And that is what Fred Davis did for us. Why do we continue to fight such a stupid battle when none exists? AA worked out a system that works like a charm. Davis, and many others, just made it more complicated than it needs to be. Read AA's discertation on the zone system, do the calibrations, and enjoy making images. Nothing simpler than that. Show me where there are errors in it and I'll follow it.

-- james (, January 22, 2002.

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