What we see all around us is the reflection against the light, and we perceive dimension and distance from shadow and perspective. Therefore, the world is a three-dimensional scope in human vision. However, this natural physics of visibility becomes a dilemma when it collides with one’s visual perception in certain conditions. Through my exploration of human optics and visual perception, I designed an interactive installation ‘distant light (2013)’. We receive a qualitative light reflection, rather than a quantitative illumination, experience that lit our visual perception. When I look toward the sun, normally, everything in my vision turns into visible and invisible. Under a light source, every subject is illuminated in human perception because light amplifies our vision, and the relationship between light and shadow becomes the threshold of human perception.