Our Opto Source is a complete stand-alone item containing 9 bright LEDs arranged in the special shape of the letter 'F'. When viewing the source with a pinhole camera the image is clearly seen inverted in the vertical plane and in the horizontal plane. This is not possible with the traditional sources such as a a candle or a carbon filament lamp. The PCB is mounted on a wooden lens holder and the Opto Source is supplied with batteries.