Set your focus on the object. Turn the DoF slider (on the lens), so that the distance (taken from the side of the camera)on the scale is on the red mark (center of scale). Your DoF will then be shown as to what aperature your using.
For example, if your using f8 and the distance is to the object is 3 feet (.9m), then your DoF will be just over 2.75 feet, to about 3.25 feet. If using f22, and your focus is 5 feet, then your DoF will be just under 4 feet , up to just over 7 feet.
Ok now that I actually re-read your post :rolleyes: , yes it is as simple as reading the side scale, then replicating it on the lens.