Article

Zone Systems Photography

In this article we are going to very briefly look at the basics behind the original zone system, before looking at the simplified zone system and how it can be applied to getting the ideal exposure in difficult satiations with digital photography or video.

Before reading this article I would suggest you become familiar with the major areas of exposure and the component parts of it. You can achieve this by reading the following, or if you are familiar with these terms just looking through them so you refresh your memory as to the basic terms and how one relates to another.

• Exposure

• Exposure required and Sunny 16 Rule   

• Exposure with an Exposure Meter   

• EV and the EV table     

• Aperture      

• Shutter Speed  

• ISO and ASA

The Original Zone System

The Zone System was developed by two tutors in 1941. from an idea that had appeared in a magazine the year before, as a means of teaching and controlling detail in black and white prints, later applied to black and white film and more recently to digital photography.

The concept is straight forward, in that an image in front of you is made up of different tones, it will also contain colours but at the moment we just want to concentrate on the tones, the level of lightness or darkness.

If we look at a scene made up of tones, ranging perhaps from snow white to pitch black, we could apply a scale, where we treated it in brightness out of ten, so our mid grey metering target or grey card is 5, black is 1 and white is ten.

 

0

I

II

III

IV

V

VI

VII

VIII

IX

X

Roman numerals were used to differentiate it from F or speeds or anything else, and you will see that there are 11 tones in total as there is a 0 as well. The description of these tones are:-

 

Zone	Description
0	Pure black
I	Near black, with slight tonality but no texture
II	Textured black,  the darkest part of the image in which slight detail is recorded
III	Average dark materials and low values showing adequate texture
IV	Average dark foliage, dark stone, or landscape shadows
V	Middle grey:  clear north sky, dark skin, average weathered wood
VI	Average Caucasian skin, light stone, shadows on snow in sunlit landscapes
VII	Very light skin, shadows in snow with acute side lighting
VIII	Lightest tone with texture, textured snow
IX	Slight tone without texture, glaring snow
X	Pure white, light sources and specula reflections

These tones were chosen as they are all one stop apart.

How these appear will differ slightly depending on the brightness and contrast of your monitor, but you should be able to see a change in most of them.

The logic from here with film and paper prints was to expose for the shadows and develop for the highlights.

The original theory then related to the way you could expose and print an image to show these tones. If the original theories interest you more, then see a Wikipedia article on it or an introductory article on another site.

Simplified Zone System

In the version of the simplified zone system, we can forget about prints and film, and cut the scale back to 9 merging 0 and 1, as they are both basically black with little detail, and 9 and 10 as they are basically so white its difficult to tell the difference. We have also dropped the roman numerals and gone back to numbers that you are more familiar with.

So our new table looks like:-

 

1

2

3

4

5

6

7

8

9

 And have the following descriptions:-

 

Zone	Description
1	Effective threshold. First step above complete black.
2	First suggestion of texture. Deep tonalities, representing the darkest part of the image in which some detail is required.
3	Average dark materials. Low values showing adequate texture.
4	Average dark foliage. Dark stone. Landscape shadow. Recommended shadow value for portraits in sunlight.
5	Clear north sky (panchromatic rendering). Dark skin. Grey stone. Average weathered wood. Middle grey (18% reflectance).
6	Average Caucasian skin value. Light stone. Shadows in snow in sunlit snowscapes.
7	Very light skin. Light grey objects. Average snow with acute side lighting.
8	Whites with textures and delicate values (not blank whites). Snow in full shade. Highlights on Caucasian skin.
9	Glaring white surfaces. Snow in flat sunlight. White without texture.

We know a number of things:-

1. With digital we usually need to do the opposite to that which was suggested for film and paper prints, and to expose so as to maintain highlights and then pull out the detail from the shadows.

2. That all cameras, including digital cameras have limited tonal range.

3. That we want to record an image as we perceive it to be.

4. The tone range you have on a modern digital camera, while not stretching to 11 stops can stretch to at least 5 stops, so looking on our scale above we can record items we perceive to be from 3 to 7 without too much difficulty. We can expand beyond this by using multiple exposure techniques and HDR, as well as some other software techniques.

5. We can apply S curves either in our cameras or more often when taking a Raw image and editing it, this allows us to compress or widen parts of this tonal range.

6. Some cameras have built in facilities to pull detail out of shadow for us, for example active D lighting on later Nikon DSLR cameras.

7. A lot of software can bring out detail out of shadow in a number of ways.

8. We can use graduated neutral density filters (grads) to, in effect, give sunglasses to a part of a scene, for example darkening the sky.

9. 1 stop = 1EV = 1 zone.

To apply this in the simplest form we could create a sketch of the scene in front of us, to a real situation, we can use our spot meter readings off the relevant points and mark them both with the variation between them as metered and the perceived value on the scale as you perceive it. With this information you can see what exposure to use so that you cover the tonal range of importance to you. Try it yourself you will find when actually doing it, it makes far more sense and is easier to do than many expect.

Applying this to allow you to spot meter off any point in an image

Normally we spot meter off something we think of as mid grey, the equivalent to our grey card or target, but we can meter off any item in the scene, as long as we make an allowance for the amount it is off the mid tone. 

So for example:-

If we experimented and found that we are able to get good detail without loosing highlights on our camera 3 stops above mid grey, then we can decide to place the lightest detail area at level 8 above.

Now if we metered with our spot meter normally off this bright area, it would set it to mid grey zone 5, producing a very dark image, so we have to make an adjustment to the exposure to lighten it so that we move this from zone 5 to zone 8, this can be simply achieved by using the exposure variation control and setting it to plus 3. On the Nikon D300 this control goes from -5 to +5.

You can see from this that by looking at a scene and deciding where you want to place the tone, you can use your spot meter in conjunction with the exposure variation control to place the exposure, to give you the result that you want, allowing you to meter off snow caped mountains, clouds, brides white dresses, or other bright areas, so no more lost highlights.

When you have taken the image check your cameras curve, and take further adjusted images if you feel it would be beneficial.

Like all photographic techniques you need to practice this and to decide the values that work with your camera.

When you get back, colours should be rich and saturated and detail should be in both the highlight area and the shadows. To see this when out taking photographs you may find it helpful to have a Hoodman Loupe  or similar, as this both magnifies and cuts out the bright daylight.

For most photographers today the most difficult part of this to start is often looking at a colour scene and seeing a tonal (black and white) range, but this can be mastered fairly quickly by gaining experience by experimentation.

 <<  ^  Exposure Article Route   ^  >>    EV and the EV table   

for details on exposure article route see the Exposure  page