I first learned about the zone system when I bought a 120 roll film camera a few years back, so this exercise was familiar territory. I took the camera on its tripod down the walking path behind my house to the river to capture some images. I took all three images within 10 feet of each other looking in different directions, the conditions were all high dynamic range but different to execute.
I took a reference shot for each image using the camera’s AV mode and set the aperture to f5.6 here are the cameras interpretations:
I then set the camera to manual set the f-stop to 5.6 and used my spot meter to measure different parts of the image, first was the dark areas, when taking a meter reading with the spot meter the result is such that the area measured will render to 18% grey so metering the darkest part of the image would render the darkest parts 18% grey and probably blow out the highlights. Here are the results:
As can be seen, the images are overexposed but in each image, a small part where the image was darkest is rendered to mid-grey.
Next, I metered the brightest areas of the image, which should create a very dark underexposed image with only the brightest part rendered to an 18% grey, the following images demonstrate the results:
The key to using the zone system is to identify the areas of the image that are supposed to be in the middle of these two images where the image should be 18% grey I took each image using these settings and the final results were as follows:
This technique allows the photographer to visualise the image and get the best spread of tones in the image from black to white.