Remote Focus Trap

Imagine setting the camera on a tripod and focusing the lens at a predefined area and when something moves into the focus area the camera automatically captures the image. This is what is called focus trap and in this sense it is a "real" focus trap where no human intervention is needed to release the shutter. The subject being photographed triggers the camera shutter via the focus sensor.

Electronic Cable Remote Shutter Release

I needed a cable/remote shutter release a few years back after I started shooting macro. The vibration caused by my hand on the camera on my cheap tripod meant the final images were not sharp to say the least. So I priced a cable release and they were just too expensive for what they were, a standard 2.5mm (mini) stereo audio plug, a bit of wire and a couple of switches. So I decided to build one.