A noiseless shutter that works inside the camera and that will give any length of exposure is made as described below. Being perfectly noiseless, they are particularly suitable when photographing children and animals. Exposures as brief as a quarter of a second may be given, which is generally sufficiently quick for such work. Construct a box A (Fig. 1) of the dimensions shown, dividing it 1 in. from the end with a strip of the same width B, having a slot 0. Through this slot and also the holes D and E previously made in the frame-wi irk a roller F, about 3/8 in. in diameter, is passed (a wooden knitting-needle answers well). In this roller burn two holes 3|in. apart, and into them fix the wire frame shown in Fig. 2 so that it hangs flat. Now cover rod and frame with thin velvet, gluing to the rod and sewing over the frame. Make a frame 1/2in. wide and 1 1/2in. deep to fit the left-hand compartment, as shown by dotted lines. This frame is afterwards covered on its inner edge with velvet, making a light-tight join. Around the roller F glue one end of a strip of tape, 2 in. long, and wind the remainder around free, joining the loose end to a strip of wood G, about 3in. long. G is hinged to the bottom with a small piece of tape also. Next wind some fine wire around a small rod to form the spring H, and fasten to this roller and the side of the framework as shown. If now the strip G is forced down, the roller is pulled round and the flap opens, but is pulled back by the spring directly G is released.

For this purpose an india-rubber bellows I on a tube is fitted at J. It only remains to fit a strip across the right-hand compartment with, perhaps, a wedge-shaped block (as in Fig. 3) to give extra pressure to the bellows. A couple of bent plates K, oue at each side, are for attaching to the camera front. The tube J projects for the pneumatic release at X. This should be fitted with a tap to keep the shutter open while focussing. The catch L and the pin M are used for the same purpose, or when long exposures are necessary and a cap must be used.

How To Make a Silent Camera Shutter.