The Zone System

[sean_merz]

<p>I know Im a little late to the party but I decided I wanted to learn the zone system. Im starting to pull my hair out. I picked up The Zone system for 35mm photographers by Carson Graves and everything was going great until he got into the application. I understand the zones. What I am not understanding is how do you move one part of the scene to a zone and not influence another? <br>

An example he gives is a portrait. He has a bush in the shade in the back and people posing in the foreground. He wants the bush in zone IV. It is metered at f/5.6 at 1/60. He wants the face in VI. It was metered at f/8 at 1/250. <br /> He goes on to say that the most important part of this pic is the skin. That it is critical it is in zone VI. Makes sense. But he then goes on to set the exposure to the bush.<br>

He keeps the f/5.6 and adjusts the shutter to 1/125. Which definitely puts the bush in zone IV. How is the skin not in zone VII now? If getting accurate skin is the most important part and he wants it in zone VI, why wouldnt he set the exposure at f/5.6 at 1/250? If the face is metered at f/8 at 1/250, opening the aperture one stop should get it into zone VI. He says by using f/5.6 at 1/125, the skin is in VI, while the shade is in IV. It seems to me, based on the lighting, that there is no way for the face to be in zone VI and the bush to be in zone IV.<br>

Any help would be much appreciated.<br>

Thanks,<br>

Sean</p>

[Bill C]

<blockquote>

<p>What I am not understanding is how do you move one part of the scene to a zone and not influence another?</p>

</blockquote>

<p>Well, for the most part you don't. You can typically pick a couple of things to control, then everything else falls where it will.</p>

<p>My guess, in your example, is that his intention is to use the exposure settings to get the (darkish) bush where he wants it, then correct the (lighter) skin tones by changing development time (this changes the contrast of the negative).</p>

<p>I'm not a zone guy, my knowledge comes from sensitometry, so someone more versed in the zone system may know better here.</p>

[AJG]

<p>The meter will give you a Zone V reading by itself. In the example you cite, to get the bush to Zone IV, you need to cut the amount of light in half, hence setting the shutter to 1/125 instead of 1/60. As Bill C. says, you could then develop the film for less time to bring the face back to Zone VI. With black and white film, you have to give enough exposure to get shadow detail, but cutting back on developing time has more effect on highlights. You are correct that the Zone system doesn't give a photographer miraculous powers to change the relative brightness of objects in a scene. What it does give you is a way to anticipate what a print will look like and to then alter exposure and/or developing to create the final image that you want. Changing development times to suit particular images is much easier with sheet film or roll film cameras with interchangeable backs, where you can use an entire roll that requires a particular development time, but the concepts involved are still valuable even if you are working with a single 35 mm camera.</p>

[CoryAmmerman]

<p>The purpose of the Zone system is to give the photographer the ability to create a negative that records the maximum amount of information relative to the intended finished product. The image capture is only the first part. Developing and printing are equally important. </p>

<p>In the example you cited, if the photographer had exposed the scene correctly for the skin tones, the background would likely have been a large mass of dark foliage with little shadow detail. If shadow detail is not recorded at the time of capture, no amount of processing will bring it out. By setting an exposure that records shadow detail, without blowing out highlight detail, the photographer can then adjust development to bring those highlights back down to the correct value. </p>

[User_5888660]

<p>The best introductory explanation of the Zone System I have found is Johnston, "The Practical Zone System." You can find a PDF of the book here: </p>

<p>http://camaraobscurablog.files.wordpress.com/2011/06/ebooksclub-org__the_practical_zone_system__for_film_and_digital_photography.pdf</p>

[jonathan_bourla1]

<p>Hi Sean.<br>

When I first tried to get a hold on the Zone System (from Ansel Adams' books), I found it very difficult. It all made sense when I attended a workshop run by photographer Howard Bond.<br>

That aside, I have some comments:<br>

1. Life is much easier if you have a light meter which measures in EV values. Also a spot meter is what you need. I have a Pentax Digital spot meter (modified by an old firm called Zone VI). Forget the modification bit for a moment, but what was important was that it came with a zone scale. For light meters without one of these scales, you can download and print your own from files on the internet. Google "Zone scale dial" or similar.<br>

2. The important thing about the Zone System is that you expose for the shadows, and adjust the film development to place the highlights where you want them. What complicates things is that using a film development time different from Normal results in a change in effective film speed. For a reduced development time (which you'd use for an overly contrasty scene), you need to give more exposure than the base meter reading indicates. You do this by adjusting the film speed on the meter. I don't know which books are good for explaining this, but once you get the hang of it, it all makes sense.<br>

3. The Zone System was meant originally for people using View Cameras which use sheet film. Here the photographer could set the optimum exposure and development for each negative. Obviously with a roll film camera all the exposures on the roll get the same development time. Some people who use a camera like a Hasselblad which uses separate film holders have two or more holders with their camera, all to be developed at different development times. Other people may have, say, two identical camera bodies (I have this in my Mamiya 7 kit, which is my secondary camera to my view camera). I noticed you mentioned your book is for the Zone System geared to 35mm cameras. I think such cameras would be the worst for the Zone System - say you had taken a great shot, and worked out the development time you would need. What do you do for the rest of the roll? Ideally you would discard the rest of the roll, and develop the film for the one good shot. But you would end up wasting a lot of film. Getting into view cameras is another huge change from using a 35mm camera, but they are well suited to Zone System use.<br>

I hope this is of some help. Good luck.<br>

All the best,<br>

Jonathan</p>

 

[lenny_eiger]

<p>There are a lot of people that make this harder than it should be. First of all, you expose for the shadows. This means you point your meter into an area that is zone 3 (or that you want to be zone 3). Deep shadow with detail... The next thing you have to realize is that your meter is set to read 18% gray, or zone 5 (by definition). That's two stops away from zone 3 (once again, by definition). This means that whatever your reading of zone 3 is, you close down 2 stops. That's all it means.</p>

<p>Then you figure out your range of light. You point your light meter at zone 7 (light highlight with detail) and count the number of stops from your one 3 reading. Photographic paper, at #2 grade was rated (at least once) at 4 stops, so if the distance between the two readings is 4 stops, the the development is "Normal". If it is more than 4 stops, you develop less. If it is less than 4 stops you develop more.</p>

<p>Now, before I go any further, some people like to use 5 stops as the normal, or "N" development. Some use other numbers like 6. The truth is, it doesn't really matter. One gets to the development times that work for them across the spectrum with some experience. Everyone's times are different (or they should be). </p>

<p>If I have a 7 stop range between my zone 3 and 7 readings, I call that an N-3. That's because 7-3 is 4, which is my normal. Basic arithmetic...</p>

<p>Calculate the exposure first, then calculate the range for your development. Most of us have a chart on the darkroom wall for N+2, N+1, N, N-1, N-2, N-3. Next to it is a time that worked for us the last time we did it. If you get it right it will seem like the image just about printed itself...</p>

<p>Good luck.</p>

[jerry_bodine]

<p>Lenny's explanation of the Zone System is good and simple. I was reminded of my first AA workshop in 1966; on the first day, Ansel introduced himself to the group and began to explain the <em>exposure formula</em> (which he explains in greater detail in "The Negative" book). Most of the eyes in the group began to glaze over quickly, but he said that with a little mental practice it becomes easy (i.e., easy for the nerd of nerds). Use of a spot meter is a huge help with the system. Many of today's spot meters are calibrated in EV units, but he describes in the book how to re-calibrate such meters so they are more useful with the <em>exposure formula</em> method (which allows for very quick exposure settings without having to read the dial on the meter.<br /> The method follows:<br /> The meter must read in candles per sq. ft. (c/ft²) or converted EV.<br /> The square root (rounded off) of the film’s box speed = key stop (aperture)<br /> e.g., ASA/ISO 125 = f/11<br /> The shutter speed, used in combination with the key stop, that produces Zone V in the metered area = the reciprocal of the c/ft²reading.<br /> e.g., 60 c/ft²reading means a shutter speed of 1/60s at f/11 would give Zone V, and if you wanted that area to give you Zone III then you’d use 1/250s at f/11 (or an equivalent combination).<br /> Important: In this example, if your film speed tests for .10 above film base + fog (fb+f) indicate, for example, a film speed one stop more exposure than box speed, you MUST apply that correction after determining the exposure of 1/250s at f/11 (or equivalent). Also any filter factor MUST be applied at the same time as the speed correction.<br /> AA used this method for the “Moonrise” exposure, as he didn’t have much time in the quickly fading light and could not find his meter. But he somehow remembered that the c/ft² luminance of the full moon at that zenith was 200 c/ft², allowing him to place the moon on a preferred zone and pray for adequate shadow detail. It missed in the shadows, but he was able to apply some toning locally in the shadows at the bottom of the negative to boost the local contrast somewhat and save it.</p>

[q.g._de_bakker]

Rather too complicated for what it accomplishes, that, Jerry.<br>Set the ISO on your meter. Point it at something and press the button. That something will now be in Zone V. If you don't want it to be, adjust exposure by as many stops up or down as desired, remembering that every1 stop change is a 1 Zone change.<br><br>Using a meter that displays EVs is helpfull. Remember whatever EV the full moon is (depends on atmospheric conditions. And i don't remember, probably EV 13 using ISO 100 film), and use that knowledge when you can't meter and want to take a photo of the moon. Remember more such usefull and more or less fixed EVs and you can expose for those without a meter too. (And if you also remember that there are things that reflect light such that they indeed are Zone V objects (the palm of your hand, green grass and such) and you will have a a fixed reference at your disposal too.)<br>There is no need to disect apertures, ISOs and shutterspeeds and start calculating in candles per square foot. Only makes something that is quite simple appear rather complicated. The Zone System is not needed for that. Where it helps is in working out how to change exposure and processing to adjust the contrast. That is complicated.

[jerry_bodine]

<p>Q.G., if I gave the impression that I was recommending that procedure, I'm sorry. I agree it's overly complex. I was just relating the method to illustrate the complexity and the reaction of the workshop participants as I saw it. I probably went overboard in presenting the details of the method.</p>

[jerry_bodine]

<p>BTW, Q.G., since that particular part of the workshop was centered on a discussion of light meters, I suspect AA was simply trying to convey to the group that those relationships of aperture/ISO/shutter speed are ONLY valid when measuring luminance of objects in candles per square foot. Some meters, such as the Weston series, were calibrated in those units at that time. Nowadays, most meters are in EV system, which is why he described in his later text how to convert an EV meter's dial to the candles/sq.ft. values. It's not complicated to do that.<br>

<br /> During that discussion he also pointed out that cds meters, also common at that time, suffered from drift of low light level readings, but said drift could be eliminated by pointing the meter at a bright light for 20s or so and then taking the reading of a shadow value, thus "pre-conditioning" the meter.</p>

[q.g._de_bakker]

Are you sure you remember that about CdS meters right, Jerry?<br>CdS meters are slow in low light, take quite a while to get to the final (and correct) reading. I don't know about CdS meter drift, but don't think that Adams confused this slow reaction with drift. Would he?<br>CdS meters also suffer badly from memory effect when exposed to bright light: they may react quicker, but can't give an accurate medium and low light level reading after being exposed to bright light. They need a remarkably/annoyingly long rest period, in darkness, to recover from exposure to bright light before they can produce accurate results again.<br>So if what you recall is indeed what he said that about preconditioning a CdS meter, he wasn't right.

[jerry_bodine]

<p>Rather than my recollection of his workshop comments, here is a verbatim quote from his text on p.74 of his book 'Camera and Lens' (1st Revised Edition, 1970), on the topic of CdS meters:</p>

<p><strong>Both zero adjustment and battery check should be observed frequently. "Conditioning" of the meter for accurate readings is described in the "Guide to Good Exposure" by James O. Milmoe, APSA (which is the best instruction book for any exposure meter I have ever seen). "Conditioning" for low-level illumination readings is very important with all meters operating with CdS cells. The meter must be exposed to moderately strong luminance areas prior to measuring low-level areas, and several seconds may be required before the meter needle stops "drifting" when directed to subjects of low luminance value. This does not imply any meter defect; it is typical of instruments of this type.</strong></p>

<p>I do not recall him mentioning (at the workshop or in any of his books) anything about lengthy recovery time from exposure to bright light, which sounds to me like something akin to the eye's response to looking at a flash where the bright spot persists for a time - a condition I've heard referred to as "persistence of vision."</p>

[q.g._de_bakker]

Thanks for the quote, Jerry.<br>Never heard or read about it before. Never experienced any of it either.

[dj_may]

<p>I no longer use N+- development. I use compensating development and expose for shadows/darkest areas in zone 3. That along with split contrast printing enables me to accomplish just about everything I did with N+- development. I should add that it took a lot of testing to find the right development to cover a variety of dynamic range scenes. In the end it is much simpler, and I prefer simplicity.</p>