Listening to Science Friday yesterday, I was struck again by the difference between the world and the world we perceive. The guest was talking about a camera that doesn’t have a lens, so it doesn’t form images. And it hit me. Lenses are the unusual things. We think of the world as the world we see, but what we see is the image formed by lenses directing light to our eyes. Those images don’t exist as such until our eyes form them.
To a blade of grass, for instance, the Sun isn’t a ball in the sky. Rather, it is the spread-out light that changes in intensity as the day progresses from morning to afternoon to evening. In the same way, the light bouncing off our bodies and going off in all directions isn’t a picture of us. It’s just light – diffuse, unfocused light. Only when a lens – in someone’s eye, in a still camera, in one of those amazing hand-held video cameras – captures that light do we become images. To most of the universe, we’re just fuzzy obstacles that block the light.
What would the world be like with light but no lenses?