The Pinhole Picture

Size shrinks with distance

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Perspective projection sends every point through a single centre onto a flat picture.
• Apparent size $h' = fh/d$: inversely proportional to distance.
• Brunelleschi and Alberti worked out the rules in early 15th-century Florence.

Steps

1. Rays through a point
2. Lamp posts
3. Frame the shot
4. Photographing the Moon
5. Image size
6. Telephoto compression
7. The dolly zoom