eli5 / why are zoomed lights in movies composed of octagons?

Question

I mean..in movies when there are a lot zoomed lights, like car lights, street lights or similar they all looks like octagons. Do you know why?

In: 1

Answer 1

It’s called “bokeh” and it’s the shape of the lens that you’re seeing – or, more accurately, the shape of the shutter that closes inside it. They come in all different shapes, depending on the lens – even triangles!