how to enable liveview ?

Hi,

i'm doing a photobooth project, based on raspberry, canon EOS 600D, and 
gphoto2.

I would like the people to see themselves in the liveview, before 
pushing the button.

So i made a little python script to take the picture when the 
photobooth's button is pressed.

Everything works fine so far, except that each time i take a picture, my 
liveview go back to menu mode.

If i take the picture with the camera's button, it stays in liveview

If i use the Photobooth's button, which triggers the command gphoto2 
-take-picture-and-download , it leaves the liveview.


Anyone as an idea why ? And better, a way to solve this problem ?

For the curious, i'm doing something similar to this :

http://www.w3sh.com/2013/03/29/photomaton-instagram/

Thanks in advance for any help


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