Off camera flash - part 2

I got hold of a hot shoe flash with the hot shoe attachment broken off. This didn't really matter as my point and shoot camera doesn't have a hot shoe fitting anyway.

Nevertheless, I was going to hook the two together so I could have off camera flash without the problems of working in the dark with slow shutter speeds as mentioned in part 1.

I found that the flash unit has two pins poking out the bottom, one sending a current (or voltage?) and the other waiting to receive it. By touching these two pins (or the adjoining wires) together I could fire the flash on demand. To link this up to my point and shoot I stuck an LDR across these wires and placed the LDR against the flash of the point and shoot camera. This means that the LDR is not letting (resisting) any electricity go round the loop of the two wires of the flash. Once the LDR gets enough light (in the form of a camera flash) it lowers it's resistance and lets the electricity flow through the loop, thus completing the circuit and firing the hot shoe flash.



Sticking this LDR on the end of some lengthy wires allowed me to get some distance between the flash and camera. The first problem I expected was that the flash might not trigger fast enough, but this appears not to be the case. Even in brighter situations where the point and shoot camera would choose a fast shutter speed the external flash still fires and is visible in the shot. In darker situations the camera needs to fire it's on body flash to focus in which case it is easiest to hold the LDR clear of the flash whilst focusing, then just press it against the flash to take the picture.