Diaphragm (optics)

The diaphragm is a part of a camera or telescope that controls how much light comes through the lens. It is like a gatekeeper for light.

Think of it like a door that you can open wide or close a little bit. If you want more light to come in, you open the door wider. If you want less light to come in, you close the door a little bit.

The diaphragm works the same way. It is a round or square-shaped piece of material that can open or close like a door. When the diaphragm is wide open, it lets a lot of light in. When the diaphragm is closed down, it lets less light in.

By adjusting the diaphragm, you can control the brightness of the image that you see through the camera or telescope. This is important because sometimes you want to see things that are very bright, like the sun, and other times you want to see things that are very dim, like stars in the night sky.

So the diaphragm helps make sure that you can see what you want to see, by controlling how much light comes through the lens.