How to take two pictures at the same time with two cameras?

Question

USB

Hello.
Problem of the following kind. There are two canon 5D mark II cameras. There is a machine running ubuntu 11.04. Cameras are connected to it via USB. The task is to make these cameras take pictures at the same time. I am using libgphoto2. When calling the image capture function, the following happens, the first camera in the list starts capturing an image, and the second returns an error that the device is locked. If you wait until the end of the first camera, then the second works as it should.
I suspect that the reason for this behavior is that the cameras work in isochronous mode and the USB bandwidth is reserved all for the first camera.
Does anyone have any information on how to solve my problem?

Answer 1

I once solved a problem like this.
In general, I’ll say according to what I had experience with: under Windows, you can synchronize 2 cameras through various tricks with the SDK. Moreover, both 4 and 5 are possible;) True, desynchronization can reach quite large values ​​- 1/100, etc.
A more reliable hardware solution: through IR synchronization or through cable desoldering is the most reliable solution, IMHO.

Answer 2

You can try using an IR transmitter. It seems RC1, RC5 will do. If they do not have any bind'a on the camera, then the two cameras will shoot in parallel.

Answer 3

The easiest way is to start shooting a frame using IR. On the Arduino, this is implemented elementarily, an IR LED and a resistor. Links to working sketches are on the site arduino.cc There is
no binding to cameras in the IR signal, shooting will work in all cameras that receive the corresponding IR signal.

Answer 4

and the remote control will not work for two cameras? I remember on Habré there was an article on how to make a remote control yourself.

Answer 5

In canon c# api (I’m talking about windows now, I don’t know how in Linux) it is possible to set the location for saving the photo (flash drive, immediately merge to the computer, and back and forth). When a snapshot occurs, an event is raised, by subscribing to which you can get the bytes of the snapshot. Two cameras have been working for me like this for two years now, 200-300 shots a day, there are no problems (in this part).
And we did the simultaneous descent in the most oaky way: a button with a pair of independent contacts and two long wires with 3.5 mm jacks at the ends. If the camera settings are fixed and you just need to take pictures, then this is more reliable than IR and radio (we tried both IR and radio synchronizers).