The obscura is a drawing aid and in its portable form was widely used by artists in the eighteenth and early nineteenth centuries. It was used by the early experimenters in photography; the desire to make the images seen on the screen permanent gave impetus to the invention of photography.

This is a typical example of an English portable obscura from the first half of the nineteenth century. Variations of this general design have either no side pieces to the hood or sides which go inside the body when closed. Some models have two or more pull-out focusing sections, often there are finger recesses on the main body to grip the focusing sections. Lenses of this period are mostly in a wood mounting, later brass mounts similar to camera lenses were used.