I saw an extreme slow motion video on the net recently which lead me to trying to take some high speed photos. My subjects were exploding water balloons. This sort of work generally requires specialised equipment but I had read of a technique possible with basic equipment.

Camera: Canon EOS 20D  Exposure: 3.2 sec (16/5)  Aperture: f/11  ISO: 200
Focal Length: 50 mm  Keywords: high speed

I dusted off the old uni bread board and built a little circuit which has a mic and customisable delay to trigger a pair of flashes when a sufficient noise is made. Interestingly during this research I found that flashes (which I always thought were insanely fast motion freezers) are only in the 1/10000+ duration range at < 1/16 power. I started out (below) with a small amount of water in a fairly well inflated balloon. This just resulted in a little puddle of water at the bottom being exposed. I then added extra water and inflated the balloon a little less (top). There were around 10 attempts of varying success. I think the next best technique might be to hang the balloon (even fuller) from something by the knot and prick it from the side. Trouble is that there has to be a certain amount to air to make a "pop" and trigger the sound circuit some distance away.

Camera: Canon EOS 20D  Exposure: 3.2 sec (16/5)  Aperture: f/11  ISO: 200
Focal Length: 50 mm  Keywords: high speed

Unfortunately this round of experimentation was cut short when some water got on the drum of the piezo mic causing it to lose a lot of sensitivity and flashes not to fire. So it was left to dry out and await another attempt to come.

UPDATE: Here is the cct. Left hand side is the mic pickup and little amp, right side the delay circuit. Plug then goes into a wireless flash transmitter. Trimpots adjust the sensitivity of the mic and the delay duration. It was operating at amount 1.5m distant from the balloon pop.

Camera: Canon EOS 20D  Exposure: 0.017 sec (1/60)  Aperture: f/3.5  ISO: 200
Focal Length: 50 mm  Keywords: high speed

Comments

23 Responses to “Adventures at High Speed”

  1. jon on March 19th, 2008 10:29 pm

    The stand to hold the balloon would also make framing easier as I never quite knew where I was holding the balloon really.

  2. jon on March 19th, 2008 10:29 pm

    Also forgot to mention that it was considered that giving the water some surface tension would make the explosion nicer – detergent was tried to some effect.

  3. Sven on March 19th, 2008 10:32 pm

    A mighty effort with that circuit, I must say. Could you pop the balloon using something that makes its own noise in the process? Are there any firearms in the house?

  4. jon on March 19th, 2008 10:34 pm

    No but I was going to try and smuggle an office nerd style, plastic pellet be-be gun back from the UK 🙂

  5. jon on March 19th, 2008 10:37 pm

    WRT to any motion blur remaining – the Canon flash was on 1/32 (around 1/20000) and the Sunpack on it’s min 1/16 (around 1/10000 aparently). Pretty fast but the Sunpack is the slowest – faster would involve another Canon/Nikon flash at 1/32.

  6. kelli on March 20th, 2008 7:17 am

    OK, not funny about the bb gun. I think they look good, sweets. I like the one withonly a little water in it cause you arms are well lit and look like coming out of nothing.

  7. Adrian on March 20th, 2008 8:29 am

    I like the bottom for the same reason – the arms and water appearing out of no where.

    Regarding the bursting – What about building a circuit with a servo & speaker?

  8. jon on March 20th, 2008 9:22 am

    Servo? A pin pricking device?

  9. Adrian on March 20th, 2008 9:25 am

    Yes – a pin pricking device

  10. Sven on March 20th, 2008 9:28 am

    A pin pricking device, you say?

  11. jon on March 20th, 2008 9:34 am

    Pin pricking device…extrodinary. I call the patent 🙂

    A good idea – would have to water proof the circuit which currently sits on a totally open bread board. I was thinking suspend the balloon and put a pin on the end of a chopstick or something.

  12. Sven on March 20th, 2008 9:37 am

    Next test – freeze a water balloon, take the rubber off, and shoot the resulting ice globe being struck with a baseball bat.

  13. jon on March 20th, 2008 9:41 am

    Hmmm. That might be a yard experiment rather than deck.

  14. Sven on March 20th, 2008 9:50 am

    Possibly… do you own a baseball bat, by any chance? I do not.

  15. Sven on March 20th, 2008 9:53 am

    I do own a surf ski paddle.

  16. jon on March 20th, 2008 9:56 am

    Sledgehammer?

  17. Sven on March 20th, 2008 9:58 am

    Now that makes much more sense! Sledgehammer and a block of ice – we are on! Just as well you no longer need the mic routing through a PC 🙂

  18. jon on March 20th, 2008 10:02 am

    No completly self contained now. Pic added.

  19. Sven on March 20th, 2008 10:29 am

    Nice touch having both PC Sync and audio plugs. Subtle product placement for Duracell there, too. When I take high-speed photos of popping balloons, I choose Duracell. Yes, only Duracell provides the power and longevity my photography demands.

  20. jon on March 20th, 2008 10:30 am

    Actually it is the nearly flat battery out of the smoke detector 🙂

  21. Jon on March 20th, 2008 1:37 pm

    Comment made from iPod touch. Well done WordPress!

  22. Adrian on March 31st, 2008 7:45 am

    What about near freezing the water – this might slow it down a fraction. You could try adding something like salt to lower the freezing temperature further. It might slow the water down but could also degrade the balloon?

  23. jon on March 31st, 2008 10:31 am

    Worth a try – and a super fun winter activity 🙂

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