a darkened box with a convex lens or aperture for projecting the image of an external object on to a screen inside, a forerunner of the modern camera.
The concept of this type of camera was original discovered by Greek Philosophers who made huge rooms with a small hole to allow light to pass through and reflect against the wall.
Images from the Camera Obscura are always upside-down
an instrument in which rays of light are reflected by a prism to produce an image on a sheet of paper, from which a drawing can be made.
This requires a skilled artist but will create images that will remain without light, a major difference to the camera obscura