Syncing flashes with multiple cameras

The TriggerBox is capable of triggering a flash/strobe unit as well as your cameras. Any flash that can be connected directly to a camera is safe to be connected to the TriggerBox. If you are unsure if your flash is compatible with the TriggerBox contact us. Some older flashes & strobes trigger at significantly higher voltages than the TriggerBox is designed to operate with.

Connecting your flash to the TriggerBox

Setting up your flashes with the TriggerBox is straight forward and doesn't take much time at all.

1. Connect your cable from your flash to a TriggerBox output (fig.1 a) This is typically a 3.5mm - 3.5mm jack cable connecting from the sync connection of the flash unit to a TriggerBox output. In this guide, we will use output 6.

Figure 1. TriggerBox rear outputs panel 1-6

2. Once you have hooked up your flash unit, you can plug all your cameras into the TriggerBox and connect the TriggerBox to your PC via a USB cable.

3. Launch the TriggerBoxController software -  download here and press connect on the software.

Figure 2. TriggerBoxController software

 4. Once the TriggerBox is connected to the software, conduct a test shot by pressing the red button at the bottom right of the screen. If the flash fires then it is receiving a signal. If it doesn't fire it is not receiving a signal. Check the cable is seated correctly and try again. If again it doesn't fire change the cable connecting the flash to the TriggerBox. If you are still experiencing problems please get in touch letting us know the make and model of your flash/strobe and we can advise on its compatibility.

5. Hopefully, all the cameras in your setup will have captured an image. If not, the first thing to check is that the settings on all the cameras are identical. With multi-camera setups, it is critical that all the camera shutters are open at the same time so it is important to ensure all the cameras are set to Manual Focus and use a slow shutter speed (such as 1/10).  If all your camera settings are the same and some cameras are still not getting a proper exposure you will need to delay the firing of the flash.

Capturing the flash during exposure

6. Flashes are much more responsive than cameras. In order for your multi-camera setup to capture the flash reliably, you may have to delay the TriggerBox output that is connected to the flash. This will ensure the flash fires once all your cameras shutters are open. The delay can be programmed using the TriggerBoxController software. 

7. The delay value can be worked out through a simple calculation using:

  • Your cameras shutter lag (response time)
  • Half of the shutter duration 

Your cameras shutter lag can be found online via Imaging Resource who hold all information about most camera models including full specification. Simply type in your camera model and view Full specification.

Figure 3. Imaging Resource website

The method to calculate the delay needed for your flash to be capture can be found below. This can be used for all cameras: 

Camera Shutter lag + 1/2 Camera Shutter Speed = Flash Delay

Below is an example of finding the flash delay when using Canon 200D cameras at 1/10 shutter speed.  

First, you will need to convert the cameras fraction shutter speed to milliseconds by dividing 1 over the bottom number and then multiplying by 1000. So in this example 1 divided by 10 = 0.1  and 0.1 multiplied by 1000 = 100 so the cameras shutter is open for 100mS. 

61mS (Shutter Lag) + 50mS (1/2 Shutter Speed) = 111mS (Flash Delay)

8. Once you have calculated your flash delay, you need to load it to the TriggerBox via the TriggerBoxController software. Simply enter the value in the delay box for the output you have the flash connected to; in our example the flash is connected  to output 6 and the calculated delay value of 111mS has been entered.

Figure 4. TriggerBoxController software with flash delay on output 6

By using this method your flash/strobe will fire roughly within the middle of the exposure window. The delay value may still need fine-tuning as some cameras shutter lag can vary with every exposure. The above calculation will get you a good starting point which you can then increase or decrease in 5mS increments to ensure a good exposure every time.

Download the TriggerBoxController software here

View Imaging resource website here