How to Use the Zone System to Learn about Metering and Exposure Compensation

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When you first move off auto, you realize how much control you have over your camera. You get to choose the aperture, shutter speed, ISO, and be able to manually select the autofocus point, among many other things. In short you get control over everything!

You also get full control over the exposure, or brightness, of the image. You decide you where to set the exposure for each image – something that the camera does not always get correct. The reason the camera doesn’t get it right all the time is because the in-camera light meter doesn’t always know how the brightness level of the subject. What tricks the light meter is bright or dark tones.

So how do you take back control of the exposure, and compensate for the camera’s errors? The process of correcting your exposure is referred to as Exposure Compensation. For more on that read: How to Use Exposure Compensation to Take Control of Your Exposure. However, before you add any exposure compensation, you first need to know how much to compensate, and understand exactly what your camera’s light meter is doing. This is why learning how to meter is important. If you are unfamiliar with the term metering, it is the process of measuring light values.

The first thing to grasp when is how your camera’s light meter sees the world. Put simply, it sees everything in grayscale. This means that all your camera sees is a world of tones; a colourless world. It cannot differentiate trees from people, people from snow, etc. (Although more modern in-camera light meters will now also recognize colour, the same basic principles apply.)

The other critical element to know is that your meter wants to make everything middle-gray, commonly referred to as 18% gray. Remember that! Write it down! Keep it with you in your camera bag until it’s firm in your memory! It’s very important!

Everything you need to know about doing exposure compensation correctly hinges off 18% gray. If your scene has a lot of bright areas in it, such as snow or sand for example, your camera will want that to be 18% gray. If you’re photographing a person in dark clothing, your camera will also want to make that 18% gray. Your camera doesn’t know your subject is actually meant to be black, nor does it know that all of that white in the viewfinder is actually snow. Leaving your camera’s meter at zero, or Meter as Read (MAR), can cause your photo to be over or under exposed.

Here is an illustration of what your camera meter will do. Tones will end up 50% grey.

Here is an illustration of what your camera meter will do. All tones will end up 18% or middle gray.

So how does knowing how your camera will meter, help you to decide how much exposure compensation to apply? This is where knowing a little about the Zone System can come in handy.

What is the Zone System?

The Zone System was developed by the late Ansel Adams and Fred Archer. In essence, it was a system used to meter and continue on in the dark room when developing images. I’m not going to discuss the Zone System in its entirety – that could be something for a future article – but at its core, the Zone System will greatly help you decide how much exposure compensation to add or subtract.

The Zone System

The Zone System

Above is an illustration of the Zone System. In it are 11 zones, denoted by Roman numerals. Here is a quick rundown of examples for each Zone:

  • Zone 0: Pure black, no detail. This is would be the edge of a negative film.
  • Zone I: Near pure black with slight tonality, but no detail.
  • Zone II: This is the first Zone where detail starts to show; the darkest part of the image where detail is recorded.
  • Zone III: Average dark materials.
  • Zone IV: Landscape shadows, dark foliage.
  • Zone V: Middle-gray, what your light meter sets to.
  • Zone VI: Average Caucasian skin tone.
  • Zone VII: Very light skin; shadows in snow.
  • Zone VIII: Lightest tone with texture.
  • Zone IX: Slight tone without texture, (e.g., glaring snow).
  • Zone X: Pure white with no detail. This would be light sources, or reflections of light sources.

This next piece of information is the other piece to the exposure compensation puzzle:

Each Zone is separated by exactly one stop of exposure.

Now that you have the information, how do you use it?! You know that you camera is metering for Zone V, or middle-gray, now consider your subject. How light or dark is it? If you were photographing a bride’s white dress, that would be very bright with texture; so going by the chart that would fall into Zone VII or VIII, which makes the exposure compensation required for correct exposure PLUS two or three stops (the difference between Zone V and where your subject should fall).

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Shot at zero exposure compensation. Black cat is gray or Zone V.

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Shot at -2 stops black cat is now black or Zone III.

As an experiment, try photographing a piece of plain white paper. First, make sure that there is no exposure compensation added – your meter should be in the middle. Take a photo. Next, add +2-stops of exposure compensation. This will bring your exposure to Zone VII. Then, take another photo. Notice the difference? The first image should be very close to middle-gray, or Zone V, where the last image should be bright white, but still show detail in the paper.

External Light Meters

Another tool that may be helpful to you, is an external handheld light meter. They work the same way as your camera’s light meter in that they meter for middle-gray, but they have the added advantage of being to reading what’s known as Incident Light: that which is falling on the subject, not reflected from it. Your camera’s meter is a reflected light meter; it reads the light that has been reflected or bounced off your subject. This may seem obvious, but there is a big difference between incident light and reflected light. Reflected light is greatly affected by tone – the darker your subject is, the less light that will be reflected, whereas the brighter your subject is the more light that will be reflected. However, the incident light – or light coming from the light source – will remain the same no matter what the tones are in your subject. By using an external light meter, you are reading the light directly from the source; unaffected by the tone of the subject.

However, do be careful when you are using an external light meter that you read the incident light from the subject’s position. You may be in the shade, for example, and your subject in the sun. If you were to read the incident light for your position,you would be getting a reading for the shade area, and not the sun, which is the light that’s falling on your subject!

This is an external light meter. It's a Sekonic L-358, and is able to meter ambient light but also meter flash.

This is an external light meter. It’s a Sekonic L-358, and is able to meter ambient or natural light as well as flash.

Summary and application

Now that you know what your light meter is doing, and how to correct it with exposure compensation, you are on your way to getting more consistent and correct exposures.

Before you press the shutter button next time, do consider what the tones in your scene are like. Are there lots of brighter tones, or more darker tones? If your frame has more brighter tones, the exposure compensation will need to be more on the plus side to render them correctly. However, if there are more darker tones, your exposure compensation will be more toward the minus side of your meter. If you feel there are equal amounts of bright and dark tones, you may find that you don’t need to add any compensation at all.

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Snow shot at zero exposure compensation is gray, or Zone V.

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Snow shot at +2 is now white with detail or Zone VII.

If you’re ever unsure of how much exposure compensation to add or subtract, take a test shot at zero, or in the middle. This will help you decide the direction in which you need to go.

Read more from our Tips & Tutorials category

Daniel

is originally from Melbourne, Australia, but now resides in the UK. He specializes in sport and editorial photography and is a photographer with the worlds leading digital content suppliers. You can see more of his work by following him on Instagram.

  • Good article Daniel. As a photo instructor, I know teaching the Grey World Theory can be a challenge. Using the old Zone System as a teaching tool was a good idea. Maybe I’m biased though. I cut my teeth on the Zone System.

    Besides Grey World Theory, I also emphasize the Sunny-16 Rule along with Equivalent Exposures. If you understand those three, then exposure is as natural as breathing.

  • wojo43

    I wish there was a more intuitive way to describe the way to adjust exposure. Saying “add a stop” is ambiguous really, in that it could mean going to a higher number OR wider lens opening. Saying, instead, “go to a wider/smaller opening” or “faster/slower speed” would be easier to understand especially for us who are still learning.

  • AB

    I learned back in the 80s to meter on the palm of my hand to get proper exposure (so long as my hand is in the same light as the subject) since palm skin tone is fairly close to middle gray for most races. A gray card you couldn’t forget at home. It isn’t perfect, of course. But it’s better than gray snow.

  • Gabi Fulcher

    You can use either aperture or shutter speed to stop up or down. Which one you choose depends on the creative effect you want to achieve in your shot. If for example depth of field is what’s really important to you in that particular shot, you might think about adjusting the shutter speed and vice versa.

  • wojo43

    Thank you Gabi for your reply. The point of my comment is with the puzzling terms we use to describe exposure adjustments and trying to teach the concept to beginners.

  • Thanks for you comment! One of the reasons we use the term ‘adding/subtracting a stop’ instead of saying ‘go to a wider/smaller aperture, or faster/slower shutter speed’ is because it completely depends on what you are trying to achieve in with your image. Saying ‘using a slower shutter speed’ may not be the best option if you want to freeze motion, for example.
    Another reason is that ‘one-stop’ is a is a measure of light of sorts. Adding one-stop exposure is making the image twice as bright.
    When first starting out, it can be a little tricky to get around the lingo, but reading the lingo all the time can help you to understand it better – if no one used the lingo, it would never be learned!

  • Caucasian skin is usually one stop brighter than middle gray.

  • AB

    Well, I did use the phrases “fairly close” and “isn’t perfect.” But maybe that’s nitpicking.

  • Bob Bevan Smith

    Another way to think of it is this: ‘Add a stop’ means ‘Let in more light’ (either a longer time the shutter is open, or a wider lens opening) to make the image brighter, and conversely ‘Subtract a stop’ means let in less light to make the image darker.
    (It is also possible to add a stop by increasing ISO – like turning up the volume on your radio – the camera amplifies the signal from the sensor and hence makes the image brighter.)
    The term ‘stop’ relates to older mechanical cameras and lenses where turning a shutter dial, or an aperture ring, you felt a click (a ‘stop’) at each setting. The shutter dial might be calibrated like 25, 50, 100, 200 as fractions of a second etc, and the aperture ring f4, f5.6, f8, f11 etc as an (inverse) measure of the width of the opening in the lens. Counter-intuitively, the lower the value, the more light you let in! Newer cameras often do not have ‘stops’ any more, giving greater control by allowing finer adjustments, such as 1/69th of a second at f6.7

  • Donna J

    Very good article to help simplify what can be a confusing subject! Thank you

  • B l u e M e s a

    @disqus_KaBTYKm4Uu:disqus When you say the term ‘exposure compensation’, do you mean the shutter speed or +/- EV button? I have Nikon D7000 and in manual mode, the +/- EV button does not show any effect where as in Aperture mode I can see the change in exposure. What shooting mode are using in tandem with +/- EV button?

  • Ach So

    Great article, thanks for the info.

    On a related note, — not so much about achieving the particular aim, but for general purpose shots where you want most of the scene to fall into the camera’s range without blown highlights or overly dark background — many people seem to only use the “default” evaluative metering mode, while for street photography and eg. contrasty landscapes, it seems in general more useful to use center-weighted average.

  • Thanks for the question! I use the term ‘exposure compensation’ because how you change it will depend on what mode you are in. For example, as you mentioned when you are in manual mode, your +/- EV button does not work. This is because you are controlling all three aspects of exposure – ISO, Aperture, Shutter Speed – and altering any one of these will alter the exposure. So, for example, if you were in manual mode and you wanted to make the image brighter, you would need to slow you shutter speed down, open your aperture, or increase your ISO.
    However, if you are in shutter or aperture priority, you are giving the camera control over one of the those three aspects. This allows you use the +/- EV button to adjust add/subtract exposure compensation.

    I hope this has cleared it up for you?

  • bskier7

    Great article. I’m interested in applying it out in the field. In the past I’ve just adjusted the exposure compensation in a very subjective manner without much thought or reasoning. For me it’s nice to have some deeper understanding what the components of my camera are actually doing so I can be more objective.

  • Yes fairly close but one stop out is double the amount of light so it could mean your exposures are out by that much. I find one stop to be fairly significant but also perhaps I’m a bit pastier white than you are. 😉 Cheers.

  • dougt

    A great article Daniel,

    Learning how to get a correct exposure with exposure compensation is probably one of the greatest stumbling blocks for budding photographers.
    The combinations of aperture, shutter speed and ISO for a given shot are not always exact due to the large number of lighting variables.
    As we can see the light meter covers the full range of Zone System from 0 to 10. The exposure compensation is really a fine adjustment setting of the actual light meter in the camera to compensate for these lighting variables.

  • Himanshu Nagpal

    nice article … learnt some thing new today

  • jgordon

    Remember that! Right it down!

    “Write” it down.

  • Daniel – thank you for your article! I’ve heard of the zone system before, but never had the examples, as you’ve outlined them, explained. You’ve made sense of, what I found to be, a complicated system. I always wondered why my camera’s histogram and light meter seemed to be at odds and I wasn’t sure which one to believe. Now I know!

  • wojo43

    Got it. These replies make the essence of the article easier to understand and, mostly, easier to pass on to my “students”. Thanks.

  • Dave_TX

    Your meter still works in manual mode. You can watch the your camera’s meter as you adjust the shutter speed, aperture, or ISO to see when the meter pointer lands on the desired + or – EV point relative to what the meter indicates is the proper exposure.

  • Charilaos

    An old soviet rangefinder made me think according the sunny16 rule for light measurement, which seems quite easy once you get used to it. Nevertheless, I think there are differences between these methods and I’d like to ask for correction if I am mistaken. The Zone System (ZS) seems to evaluate reflected light and its purpose seems to be deciding on exposure compensation (based on the current article). The sunny16 seems to evaluate incident light and I’d say that its purpose is to take a light measurement (or an estimate). The Gray World Theory you mentioned seems targeted in correcting white balance. So I guess the three “methods” are meant for different things. All useful in their fields, yet different.

  • Reflective metering, incident metering, and Sunny-16 are all just metering techniques that were based on the Gray World Theory. Basically, on average everything you photograph will reflect 18% of the light into your camera. But, as I’m sure you know, that’s not always the case. That’s where systems like The Zone System and just good knowledge of exposure comes into play. You know that white and black object are going to photograph as grey unless you understand the shortcomings of metering and make the necessary adjustments. To me, I don’t see these techniques as different. Rather, I see them as all part of the bigger whole which is metering and exposure.

  • Charilaos

    ok, I see your point and I agree. In the meantime, I did some reading and understood (a bit) better how the Zone System works. Could you suggest an article I could read regarding the Gray World Theory? I only did a fast websearch on that. The first time I read it was in your initial post. Thanks in advance!

  • I am trying to find you something of value. I learned about it from the books and professors at Rochester Institute of Technology. Most of those professors had close ties with Kodak a few miles away. Unfortunately, I sold off all of my film based books years ago. Anyway, I hope to find you something good to read.

  • There isn’t much (if any) discussion on the actual gray (or grey) world theory or assumption. It’s a very old theory. There is, and always has been, discussions on whether it’s an accurate theory. Most argue that it’s flawed by a few percentages. Then when you get into the realm of color photography, there’s even further dissension amongst photo scientist. Here are four articles you can read over that might help you. Warning, these are heavy on the math and science.

    http://www.largeformatphotography.info/articles/conrad-meter-cal.pdf
    http://dpanswers.com/content/tech_kfactor.php
    http://phototechmag.com/do-light-meters-see-the-world-as-18-gray/
    http://phototechmag.com/is-18-gray-a-myth/

  • Charilaos

    Thank you VERY much for your time! I will read the articles you referred to with great interest! Science and math are very welcome to me, as I happen to be a physics teacher. Since you mentioned old books, I’ll also take a look at some photography books that my brother has, who never really got the “photo bug”. I remember seeing chapters regarding b/w development and printing in the darkroom. I’ll go pick them up and do some reading in the metering part (until I decide to get more serious and read the entire books). Thanks again, I really appreciate your help!

  • Glad to be a help. Here’s the main book I got my knowledge from. It was written by some of the professors I had at RIT. Book is long gone now. Can’t remember what all was inside it.
    https://www.amazon.com/Photographic-Materials-Processes-Compton-Stroebel/dp/0240517520

  • Charilaos

    Thanks, I’ll keep it in mind!

  • Houdi Tv at Utube

    That’s the explanation that I was looking for. Thank you so much. Since I always shot on manual it means I don’t need EV, right?

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