When two cameras are looking at the same subject from opposite directions, and require different lighting (as one camera would be looking straight at the opposing lights), if camera A and strobing light A are out of sync with camera B and light B, each would only benefit from its own light source, and not suffer from reduced image quality from having unwanted light on the subject.
By delaying the sync out signal by half the interframe time (eg 500us (microseconds) at a framing rate of 1000fps), the slave camera and the light (connected to the master) activate at the same time.
With the other light source connected to the external sync of the slave camera, the delay of the light is double, as its working form a delayed sync signal, and the camera introduces a further 500us delay, putting the light back in sync with the master camera.
This is a valuable technique for imaging when the position of the lights does not need to be compromised, just because of other camera positions requiring different lighting.
See an explanation of the set up, how it works, and how to set the software up, please see the tutorial on the IDT Youtube channel.
Suitable lights include LED lighting from IDT
More information on MotionStudio, the software capable of controlling the timing and sync’ing of cameras and strobing lights.