|A sneak peak of the finished device|
After the purchase of my Pentax K-7 a few years ago I began to experiment with long exposures, specifically "bulb" exposures. Bulb mode, sometimes abbreviated with a "B" on camera bodies, is a shutter speed setting that allows for extraordinarily long exposure times. When enabled, the shutter stays open as long as the shutter release button remains depressed. This is great since we can exceed the exposure times supported by most DSLR and SLR bodies. For instance the K-7 can do exposures automatically up to 30 seconds, but past this the bulb mode must be used. It is slightly annoying, however, since the shutter must remain depressed for the full duration of the shot. See how I solved this after the jump.