What is the primary function of a camera obscura?

The primary function of a camera obscura is to project an inverted image of the outside scene. This optical device operates on the principle of light traveling in straight lines. When light from a scene passes through a small aperture in one wall of a darkened room or box, it projects an image of that scene onto the opposite wall. Due to the nature of how light travels, the image produced is inverted both vertically and horizontally.

The design of the camera obscura has been pivotal in the development of photography and understandings of perspective and optics, as it demonstrated how light can be manipulated to create images. This simple yet effective method allows for a clear representation of the external environment, illustrating the fundamental principles of image formation.