In this activity, students will investigate the operation of a pinhole "lens" and compare it to the eye.
The image cast through a pinhole in a pinhole camera has the property of being in clear focus at any distance from the pinhole. That's because the tininess of the pinhole does not allow overlapping of light rays. (The tininess also doesn't allow the passage of much light, so pinhole images are normally dim as well.) When a pinhole is placed at the center of the pupil of your eye, the light that passes through the pinhole forms a focused image no matter where the object is located. Pinhole vision, although dim, is remarkably clear. In this activity, you will use a pinhole to see fine detail more clearly.