I struggled to understand what this exercise was aiming at. It seemed to me to be considering the depth of field of a landscape photograph, rather than a moment in time. I carried out the task as described. I went to an old quarry which has been turned into an amenity for walks, picnics etc. I was able to look at the fence, and tree close to, and then across the valley to the distant cornfield where a combine harvester was throwing up a great deal of cloud. I then took the photographs, changing the viewpoint slightly with each photo.
