There are several beam/sound triggers available but I like a challenge and decided to design and built a light beam/sound trigger. Being a retired electronics engineer made this possible. My primary purpose was to do water drop/splash photography. Placing a light beam trigger to activate when the drop was about 18 inches above the water pool provided more than enough time to cover the camera shutter delay. I had the flash triggered by the camera in manual mode with the camera shutter release triggered from a cable connected to my adjustable time delay box. Camera on a tripod set to manual mode, manual focus. With this set up I was able to work in low ambient light since the flash, even at 1/32 power, was able to dominate over the ambient light. I made an adjustable time delay circuit that triggered from the time the drop passed a led sensor. Sound sensing was also included but I have not used that feature yet. Obviously, you will need something to give a trigger signal at least the amount of the camera shutter delay for this to work as it should. For example, to capture the burst of a balloon, I would drop a match stick pin dart from 2 feet above the balloon and use the led beam trigger just after the dart release. I would then fine tune the adjustable time delay circuit to match the time to impact of the dart with the balloon. This way you get reliable repeatable shots of what you want.

If you need sound as the trigger, then one needs to generate a sound (or light signal) a few hundred milliseconds ahead of the time when the shot is to be taken. The sound of the event to be photographed will normally not be useful as a trigger since the camera will trigger a few hundred milliseconds later and for many events, this will be too late.

Good luck to all with automatic triggered shots.

Good luck.

Thank you all for your helpful advice and ideas.

Shutter lag is in all cameras as this link shows (https://www.imaging-resource.com/PRODS/canon-5d-mkiii/canon-5d-mkiiiA6.HTM), regardless of how new camera is, it does take some time for the mirror to move, etc. That said, the smarts of the camera need to coordinate with the firing of the flash. With the MIOPS, it sends the signal (I assume) to both at the same time and therefore, the flash goes, then the shutter releases after the mirror has moved, etc.

I may be wrong, but I thinking that if the MIOPS were to send the info to the camera and the camera were to trip the flash, then they would be in sync, but delayed by the 59 ms or so and possibly miss the balloon's popping. For lightning, the flash isn't used and the amount of time that the lightning is striking is longer, I assume. I assume that because I have shot lightning successfully with just triggering when I saw the lightning, but that is based on a lucky longer strike. MIOPS says that the shutter lag isn't a problem with lightning capture.

Even though capturing the bursting of balloons has been done forever, it hasn't been done by me and I would at least like to see if I can accomplish what may be "old hat" to others. Therefore, I will seek to try and capture a few this week, maybe even tonight. As I get something worth displaying, I'll post some probably in the gallery or in the critique area because I love to have folks tell me how to improve or what might work better.