Light Lab · Aperture

occlusion → volumetric shafts refraction → caustic pool

Cut the beam

The window bars block part of the beam. The open gaps let shafts through. A lens bends the light that gets through. Where those bent rays pile up, a bright pool forms.

Drag orbit · scroll dolly

Where you'll see this

A cinematographer sets the f-stop, which changes how wide the lens opening is. A wider opening lets in more light. A smaller opening lets in less light and keeps more of the scene sharp.

A gaffer cuts a lamp with a flag or a window. Dust and haze scatter the light that gets through, so the beam shows up as shafts.

A photographer shoots sunlight through a glass of water or a pool. The curved surface bends the beam that gets through, and the light piles up in a bright pool.

Common mistakes

A beam does not glow by itself. Shafts show up when dust, haze, or smoke scatters light toward your eye. In clean air you mostly see the spot where the beam lands.

A smaller opening does not only make a picture sharper. It also lets less light through, so the room or the picture gets darker.

The bright pool is not a shadow. A shadow is light that was blocked. The pool is light that a lens bent until the rays piled up.