Firing multiple cameras at the same time

Part of an array of 120 Canon EOS 30D cameras controlled using 5 laptops running
DSLR Remote Pro Multi-Camera


There are two ways multiple cameras can be fired at the same time using DSLR Remote Pro Multi-Camera which are described below. In order to eliminate variable delays due to auto-focus the cameras should be set to manual focus and pre-focused before taking the photos.

With PSRemote Multi-Camera it is only possible to trigger the cameras using the first method. To minimize variations due to auto-focus delays the cameras should be pre-focused by selecting AF lock in the main PSRemote Multi-Camera window. Using AF lock you can usually synchronise multiple Canon PowerShot cameras to within less than 1 ms.

  1. Using DSLR Remote Pro to trigger the cameras:
    This can be done by selecting "Gang camera shutter releases together" in preferences and then pressing the "Release" button in the main window. DSLR Remote Pro instructs each camera to take a picture as quickly as possible and each camera will be triggered in turn with a delay of approximately 1/6 sec between each camera. This means if there are 18 cameras it will take approximately 3 secs from when the first camera takes a picture until the last camera takes a picture.
    When capturing video the cameras will start one after the other with a delay of approximately 1/10th sec between each camera.
  2. Triggering the cameras using the remote release connection:
    Canon EOS cameras have remote release sockets which allow the camera to be fired by simply using a switch. Multiple cameras can be fired at the same time by plugging cables into the remote release socket of each camera and witing these together to a master switch. The cameras won't all trigger at exactly the same time due to variations in the response time of each camera but they will usually all fire within approximately 1 ms to 5 ms of each other (the variation depends on camera model, lens type etc.). This variation can be reduced by activating the auto-focus via the remote release cables just before taking the photo.


Using the remote release socket to fire multiple cameras at once

All EOS cameras except the Canon EOS 60D, Canon EOS 400D/Digital Rebel XTi, Canon EOS 450D/Rebel XSi, Canon EOS 500D/Rebel T1i, Canon EOS 550D/Rebel T2i, Canon EOS 600D/Rebel T3i, Canon EOS 650D/Rebel T4i, Canon EOS 1100D/Rebel T3 and Canon EOS 1000D/Rebel XS have a proprietary three-pin remote release socket shown below. The 400D, 450D, 500D, 550D and 1000D use a simpler standard 2.5mm jackplug with three connections and works in exactly the same way.
Remote release switches and cables can be bought as accessories from Canon or more cheaply from eBay.

The remote release switch has two positions similar to the camera's shutter release button. Half-pressure on the release switch activates the camera's auto-focus by connecting the "Ground" and "Activate AF" pins together. Full pressure on the release switch releases the camera's shutter by connecting the "Ground" and "Release Shutter" pins together. It isn't necessary to activate the auto-focus in order to release the shutter and a picture can be taken by only connecting the "Ground" and "Release Shutter" pins together. Activating the auto-focus releasing the shutter puts the camera into a heightened state of readiness and will reduce the variations between cameras.

Canon EOS-1D X, EOS-1Ds Mark III/EOS-1D Mark IV/EOS-1D Mark III/5D Mark III/5D Mark II/6D/7D/50D/40D/30D Remote Release Connector

Canon EOS 30D connectors (remote release socket is bottom left)

Remote release socket for Canon EOS 30D/40D/50D/6D/7D/5D Mark III/5D Mark III/5D Mark II/1D Mark III/1D Mark IV/1Ds Mark III/1D X showing pinout

Canon EOS 60D, 400D/Digital Rebel XTi, 450D/Digital Rebel XSi, Canon EOS 500D/Rebel T1i, Canon EOS 550D/Rebel T2i, Canon EOS 600D/Rebel T3i, Canon EOS 650D/Rebel T4i, 1100D/Rebel T3 and 1000D/Rebel XS Remote Release Connector

Canon EOS 60D, 650D/Digital Rebel T4i, 600D/Digital Rebel T3i, 550D/Rebel T2i, 500D/Rebel T1i, 450D/Digital Rebel XSi, 400D/Digital Rebel XTi, 1100D/Rebel T3 and1000D/Rebel XS Connectors
(middle socket is the remote release socket)

2.5mm 3-connection Jackplug for the above cameras.

Triggering the cameras from a PC

The simplest way to trigger the cameras from a PC is to use a USB controlled relay such as this low cost bus-powered 2-channel USB relay: USB-RLY02 or USB controlled relays from phidgets.
National Control Devices LLC have a wide selection of more sophisticated PC controlled relays including 16-channel devices and USB, ethernet or wireless communications. Programming these devices is usually very simple and generally involves sending commands to open and close the relays to a virtual COM port. You will need to write your own software but any competent programmer should be able to do this. Mechanical relays are cheap and easy to use but will only be accurate to within a few 1/100ths second. More accurate synchronisation can be achieved by using solid state relays, transistors or opto isolators.

A typical setup to control and trigger 16 Canon EOS cameras from a single PC with 2 spare USB ports would consist of:

  1. A PC or laptop running Windows 7 or Windows 8 and our DSLR Remote Pro Multi-Camera software
  2. A 4 port USB hub connected to one USB port on the PC with a further four 4 port USB hubs connected to each of its ports. The USB cables from the cameras plug directly into the USB ports on the USB hubs. The USB hubs should be externally powered for maximum reliability.
  3. A two channel USB controlled relay plugged into the second USB port on the PC. The relays are then connected to the remote release sockets of the cameras: one relay is used to activate the cameras' AF and the other to trigger the shutters.
  4. Software to control the relays and fire the cameras. Alternatively the cameras can be trigger manually by connecting a remote release switch to the cameras' remote release sockets and using a few diodes as shown in the "Simple passive trigger system" below.

Please note: The maximum USB cable length allowed by the USB standard is 5m (approx 16 feet). This can be extended by using USB hubs but you are only allowed a maximum of 3 hubs daisy chained together (giving a maximum cable length of 20m). You can buy active USB cables which can be daisy chained together but please be aware that these are really cables with a self-powered USB hub on the end. Self-powered USB hubs draw power from the USB interface instead of using an external power supply and tend to be less reliable than externally powered hubs.

In operation DSLR Remote Pro Multi-Camera is used to control the camera settings and manage the downloading and naming of the images and the USB relay is used to trigger the cameras.

A simple passive trigger system:

A simple active trigger system controlled by a microprocessor:


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DSLR Remote Pro Multi-Camera - Remote Capture Software for controlling multiple Canon EOS-1Ds Mark III, EOS-1D Mark III, EOS 7D, EOS 60D, EOS 50D, EOS 40D, EOS 30D, EOS 400D/Rebel XTi, EOS 450D/Rebel XSi, EOS 500D/Rebel T1i, EOS 550D/Rebel T2i, EOS 600D/Rebel T3i, EOS 650D/Rebel T4i, EOS 1000D/Rebel T3 or EOS 1000D/Rebel XS cameras