High Speed Primer - Triggers
On our last post we went through the basic ideas of capturing a high speed photograph, and today we will cover some of the basic triggers and kits available to play the high speed game.
So, we need a small and preferably cheap electronic gizmo that will be triggered when an event such as a passing cherry or a popping balloon occurs. We need it to then fire a flash unit, or even the camera shutter for slowish events like a bird taking off. (The camera can then fire the flash in the normal way that cameras do!) The range of triggers – and sensors for the various types of event - is quite extensive now.
You can make your own, buy a kit, or buy a ready-made system. I went with home-made, and not just because I’m cheap! For me, part of the fun is in the making, seeing what I can do for myself.
This isn't a comprehensive list, and do leave a comment if I've missed a helpful link, but the commonly discussed triggers include these:
Build A Kit
Cheap and cheerful! This isn’t hard, if you are even just a BIT of a tinkerer. A google search for “high speed photography DIY” or similar will turn up gazillions of ideas including circuit designs.
You will need two basic items and then you can add as many sensors and peripherals as you like depending on your needs. (You can even hook up the setup to an arduino to turn the lights off for you).
- Controller - The brains of the system is actually not that smart: it includes a way to sense an event and send a command for a flash to fire. Since this is really not that much, simple controllers can be bought or made for really cheap. More sophisticated controllers have the delay circuit integrated, a built in sensor or two, a sensitivity adjustment button and even an option to hook up to an Arduino board.
- Delay - Usually, there is a small time gap between the triggering event and the time you want the flash to pop. For example, the sound of a BB gun may reach the sensor before the pellet hits the target, in that case, you want to add a bit of a delay so the flash will fire on impact.
- Sensors - sensors are the eyes and ears of the system. They will let your controller know when an event has happened. The most basic sensor is a sound sensor, but there are many more.
- Sound - This sensor will fire once it hears a loud noise, like a clap or a popping balloon.
- Beam - this sensor will fire once a beam (light, Laser, IR) is broken. It is often used when shooting water drops.
- Light gate - (or photo gate) very similar to the beam only it has both the beam sender and the reciver in a single unit.
- Contact - This sensor fires when two elements touch each other, it is actually a very simple sensor that only takes minutes to build.
- Other? you betcha! all the trigger does is send a simple signal to the controller. How simple? It usually just closes a circuit, so any thing that can close a circuit will work.
Kits For Assembly
Ready made kits come with all the components included, sometimes they do not even require soldering skills as they come with a breadboard. The results are often homey looking, but they provide the same functionality.
The excellent hiviz is where I got both the designs (freely available on that site) and the components (in the form of their kits) for my original stuff. There are even “build it by numbers” guides to get you up and running. HiViz now sell their kits ready-built too. A great way to get started for little money if you just want to experiment and try things out.
The HiViz Multi-trigger with sound and photgate triggers and a delay circuit is now available built and boxed, with suitable cables, for $275. Remember, the same circuit - to put together yourself on a breadboard - is $25 on their website. It is a classical Time vs. Money thing. The assembly is not that hard and requires no soldering if you use the provided breadboard.
The more ambitious Camera Axe system can also be bought as a kit, as can the Quaketronics controller. Both of these kits will end up being advanced pieces of kit, and will require more skill with a soldering iron than average, I reckon - just so as you know! On the other hand, the entire kit is released on a GPL license so you can go ahead and build your own version of it.
The Arduino programmable boards are being used too. Camera Axe version 5 can be bought as an Arduino Shield kit – but you need the Arduino as well, of course.
Ready Made Boxes
Ready made boxes comes in all kinds and flavors, with different levels of functionality.
For non-tinkerers, there are several well-known triggers and sensor-sets. A more expensive route, and representative prices were looked up today... [in November 2011]. Non-US buyers remember that your country's customs may charge import duty - in the UK that is 33% on orders over £18 (gbp). Yes, ouch.
The HiViz Multi-trigger comes in an assembled box too. It has a great finish and the kit is a wonderful piece of electronics. It is super simple to use and it supports all the various functions that the un-assembled kit supports. This is the only kit I recommend getting as a kit rather than a box, since it is a great experience to put it together.
(we tried to match the prices so they all include the same range of sensors and outputs, this is why pricing would be a bit differnt than the stand alone kit on the linked pages).
The Camera Axe is very popular. Kit form available, and ready-built, and there are sensors galore. Now available as an Arduino Shield kit too for $85, but you need an Arduino Uno as well. A starter set for a tad under $300 (US) could be Camera Axe $185; Hot shoe connector (one flash) $25; Camera Connector $20; Sound sensor $20; Laser plus light sensor (for a photogate pair) $40
The Stop Shot is a a similar starter kit at about $370.(it has the nicest box around)
StopShot are kinda big on water drop photography and being used by many of the drops photographers for their excellent valve system.
The Mumford Time Machine is yet a similar kit. It has been around for very long and reports so far has been good.
I have not had any experience with it. Getting a kit will all the relevant sensors will set you back about $420. While it is a great kit, it rankes the highest on price in the list.
The Quaketronics kit is or was available as a kit or built - but I note that it is marked as "currently unavailable" on the order page in October 2011.
Regardless if you are getting a ready made trigger, a high end kit or tinkerring around with arduino, you can always add more pieces as you go along and expand the system as you go.
On our next post we will build a basic trigger, and take our very first high speed shot.
About The Author
Brian Davies is a photographer and a Retired educationalist based in Hull, UK. You can follow his flickr stream here.