Here is a simple way to construct a camera for a pocket photographic apparatus.

Cut out of strong cardboard a piece of about 2 to 2 1/4 inches square. In the middle cut out a circle a little smaller than the lens with which you cover it, so that this lens holds on the edge of the hole.

Cut out also two triangles of cardboard, having one side equal to the square, and a length in proportion to the focus of the lens; say for a simple lens of 3 inch focus, and one inch diameter, a length of one and a half inches.

Paste the two triangles on the square at A and B, their base C must hold a rectangular mirror of the same dimensions as the side C of the square and the side of the triangles. On side D fix a roughened glass pane, or instead, a thin transparent sheet of paper; tissue paper for example.

Cut a black piece of cardboard as indicated in Fig. 3 C; the dotted lines indicate the sides to be turned down. This shade is fixed on to the camera.

Pass through the holes, S S, an iron rod or a long needle, which must pass likewise through the upper angle of the triangles, forming the sides, (Fig. 1). When your lens has been fixed on the round hole of the square your camera is complete.

The shade produces complete obscurity so that the operator can see in the middle of the camera the object or person he wishes to photograph.

In order to fix it on the photographic apparatus, one may fasten a wire, in the form of an elongated U, just below the mirror at E.