eli5 Why does light appear as hexagon from a distance?

Question

eli5 Why does light appear as hexagon from a distance?

In: 5

Answer 1

That’s just an artifact of most of the lenses we use. The hexagons you see are called flares, it’s an optical weakness of the lens, in particular the diaphragm that lets you control how much light passes through the lens. This diaphragm opens and closes with lamella that rotate into each other and cause the diaphragm to close just like the iris in your own eye. Cheap lenses use 5 lamella, and if you close such a lens, the hole produced is not round, but a pentagon. The shape of this hole is what you see as flair.

Answer 2

That’s just an artifact of most of the lenses we use. The hexagons you see are called flares, it’s an optical weakness of the lens, in particular the diaphragm that lets you control how much light passes through the lens. This diaphragm opens and closes with lamella that rotate into each other and cause the diaphragm to close just like the iris in your own eye. Cheap lenses use 5 lamella, and if you close such a lens, the hole produced is not round, but a pentagon. The shape of this hole is what you see as flair.