Adding light to nearly any composition can change the intensity or mood of a certain photo. Many technique can be used when adding light to a composition. If your light is spread out on a subject, that subject will appear to be lit evenly and appear plain. On the other hand if your light is focused on one point of a subject, the subject will can appear sinister or intense where the light does not reach the subject. The flower in this example has a light focused on the middle of the flower giving the flower a more intense feel and look.
Nicely stated. the light is narrowly focused and not falling at all on the background letting it go completely black.