Saturday 4 June 2011

DIY High-speed Photography

Capturing High speed moments isn’t that difficult as it may seem. All it requires is a simple set-up, a little knowledge if electronics (for a trigger mechanism), and there you have it. Below is a sample form my set-up, that included Canon 1000D, YN467 Speed lite, a sound trigger circuit I made myself with a bit of help from the internet, a dark room, and a common pin :)


Sound triggered snap of a balloon bursting.


So, two major difficulties are needed to be tackled to freeze time.
    • Firstly, very high shutter speed is required. Most of the basic, or even the most sophisticated ones have maximum shutter speed of around 1/8000s, that too will require enormous amount of light, as flash will restrict this number to around 1/250s. This is quite fast, but not as fast as one needed to freeze time as in the above picture. Effectively, the above picture is at around  1/51000s shutter speed, more than you will find in any camera on shelves.
    • Secondly, the timing. It all happens in a blink of an eye, so manually pressing the shutter release is not an option.
In order to get the first problem solved, we are going to set the camera in a dark room and in Bulb mode, and use the f-stop settings in speed light capture the frame. In my case, I used Yongnuo YN467 Canon compatible speedlite. This gives 1/800s flash duratiotion at F1. With maximum F-stop at f/64, this flash gives me minimum exposure duration of 1/51200s, which is quite fast. This is used in the above picture.


For the second problem, a trigger mechanism was required to fire the flash at the moment the balloon was burst. For this, I used the circuit form link. This consists of a pre-amplifier for electret microphone, and using the signal to drive an opto-traic, which in turn was connected to a hot shoe from an old film camera to trigger the flash. Below is the final circuit I made.



Final sound trigger device, with shutter release switche


Now for the final shots, the camera was set with bulb mode, aperture down to around f/11 to keep exposure minimum, with room lights on and camera in  manual foucus mode, the final frame with balloon was done. I took a couple of pictures before bursting just to make sure that the focus/framing was perfect. Then, the Speedlite was connected to the circuit, and placed such that the main beam hit the balloon when fired. Mic was placed near the balloon (distance between the sound source and the mic result in which stage of the balloon burst is captured).

Now with the lights turned off, the camera shutter is opened in bulb, but as the room is dark, and we are using f/11, hardly and detectable exposure is done. When the balloon is punctured, the sound caused the flash to trigger, which in turn caused the complete exposure of that instant (1/51200 s or 19.53 micro seconds for my case). after closing the shutter, we have successfully captured the instant.

A few of my example shots are shared below:




Image of a a balloon bursting. Captured using sound trigger with mic at a distance.

Water gushing out of a water filled balloon

A screwdriver thrown at the balloon, sound triggered snap at impact

My further photos can be view at my Flickr account.

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