This image shows the contrast between the center of the sunflower with the brightness of the petals. The photo also really goes into detail with the petals and seeds in the middle, you can really see the individual lines of the petals. The direction of the light is coming from the upper left side and is shining down onto the details of the petals and the light shines through them to capture the detail of the seeds.
This is a good example of an extreme close up.