Start with the metered reading and first double the exposure by opening up one stop, which is the equivalent of increasing the exposure by one zone. From f/16 @
Next, double the exposure again to place the snow in Zone 7. From f/16 @
Each doubling of the exposure makes the snow one zone lighter in tone. You can even go a half tone lighter by using the aperture setting between the f/stops shown on the camera. Thus, to place the snow in Zone 7½, go from the Zone 7 setting of f/16 @
With this example, you have learned how to expose negatives using the zone system. The critical point to remember is that the gray meter always gives a Zone 5 reading. You must open the aperture or increase the shutter speed if you want lighter tones than Zone 5. You must close down the aperture or decrease the shutter speed if you want tones darker than Zone 5. Then, by maintaining a mental image of the tonal value of each zone, you can determine exactly how much to open up or close down to obtain your desired exposure.
It may be confusing at first to realize that when you are standing in front of a bright object (such as sunlit snow), you must open up the lens to make it bright. It seems logically correct to close down the aperture from your meter reading because the object is so bright, but the opposite is true. You always start from the Zone 5, medium gray meter reading, and if you want your subject to have tones lighter than Zone 5 you must give it additional exposure above the meter reading to make it light. Similarly, starting with the Zone 5 medium gray meter reading, if you want your subject to have darker tones than Zone 5, you must give it less exposure than the meter reading to make it dark. Just as you must interpret the scene rather than merely “shoot” it to make your point of view visible, you must also control the negative densities. You can do so if you recognize that your starting point is always medium gray, the exposure that the gray meter always gives you!
Review of Negative Exposure Procedure
Let’s quickly review the procedure for obtaining a proper exposure. In a sense, you must start at the end, jump to the beginning, then work back to the end. It works this way: when you see something you want to photograph, first decide the tonalities you want in the final print (that is the end point!). Then take your meter reading, which always gives you a Zone 5 exposure (that is the starting point!). Then decide how many stops (i.e., zones) you must open up or close down to reach the desired tones (that is working back toward the end point!).
This tells you that the use of the zone system is integrally tied together with previsualization, for you must be able to visualize the way you want the final print to look in order to follow this procedure. Most of the time, if you follow your light meter (the gray meter) blindly, you’ll probably come out relatively close to the proper exposure because the eye is somewhat of a gray meter also. After all, you see things almost equally well outdoors or indoors, even though the light levels are very far apart. This is due to the fact that the eye and brain compensate wonderfully within a very wide range of brightness levels—in other words, you average out the light levels, just like the meter does. But when you encounter an exceptional situation such as the sunlit snow, following the gray meter can be disastrous. You will end up with Zone 5 snow! Therefore, keep in mind that the gray meter is a dumb robot. It is your tool, and it gives you a starting point—middle gray—a point of departure. It is up to you to depart with intelligence.
Consider another example, along with several variations, to help solidify these ideas. Suppose you travel to Hawaii and are standing on a field of black lava rock on a cloudy day. You decide you want to photograph the rock. First, look at it and decide what tonal values you want it to have. Using a mental picture of the zone scale, you might choose an average tone of about Zone 3½, so that the textures are quite dark yet easily seen.
Next, take a meter reading with your gray meter. Suppose the meter reads f/5.6 @
This time, let’s leave the shutter speed at
In this example, you cut down on the exposure from the meter reading in order to make the object (the lava rock) appear as dark in the print as it did to your eye. You started with the Zone 5 reading and closed down 1½ zones to Zone 3½. Suppose the field of lava rock also includes a bush with delicate, lacy branches that sway gently in the breeze. If you want to arrest the movement of those branches,
Note
The zone system is a method of precise exposure, and that precision can be applied to literal interpretations or to vast departures from reality. It is a remarkably useful and flexible system of exposure for creative photographers.
Now, suppose there is no wind and you want maximum depth of field. Smaller apertures (i.e., the higher f/stop numbers) yield greater depth of field, and the setting between f/8 and f/11 may not yield sharpness from the immediate foreground to distant areas. If you stop down to a point halfway between f/11 and f/16, and compensate for the loss of one zone by increasing the shutter speed from