automatic shutter release

Only the most expensive cameras have shutter speeds slower than one second. This can be rather incon- venient if long exposures have to be made, since these have to be made by using the `B` setting and timing the exposure using a watch. The unit described in this article will allow long exposures to be made from one second to 1 00 seconds, and can be used with any camera that will accept a cable release, and has `B` shutter setting. It may also be used as a remote shutter release and as a self timer for cameras that do not have this facility.