Hi,
is it possible to synchronize two action 2 (for stereoscopic photography / movie)?

As far as I know that is not possible.  

thanks!
i will ask DJI for this feature in the next version of this action cam...

Hi there. Thank you for reaching out and sorry for the late response. Unfortunately, we don't have this feature on the DJI Osmo Action 2. I will take this as a suggestion of yours and will forward it to our designated team for attention. After the evaluation of the engineers, significant suggestions or requests will be implemented via the firmware update, app update, etc. For any updates, please stay tuned to the latest news on our DJI official website at www.dji.com. Thank you for your valued support.