What do you mean by black box?

The space inside the camera is opaque when it is closed, and the lens, shutter and film are all in front.

Camera obscura, also known as cassette, is an optical instrument that can project images on the screen.

The concept of background black box appeared as early as BC. Since15th century, it has been used by artists as an auxiliary tool for painting. By the end of18th century, some photographers had carried out photography experiments in black boxes.

Network explanation? A sealed box has a small hole on one side, and the scenery outside the box passes through the small hole, forming an opposite reflection on the completely dark inner wall of the box. This is the earliest form of camera. There is also black-box operation: it is to operate privately and not let others know.

Application mode

When taking pictures with a camera, the farther away the object is from the camera, the shorter the camera box should be, and when taking pictures of nearby objects, the longer the camera box should be, that is, the lens should extend forward. Camera box is an optical instrument that can project images on the screen.

A black box is an airtight box or a dark room without light. Cut a small hole in the box wall, let the light and shadow of the object outside the box pass through this hole, and form a reflection on the inner wall of the box. A painter can sit in a box and lay paper on the reflection to draw an image.