@FGS and GullWhiz: Thank you.
@GullWhiz: the funny thing is , I thought I switched out the camara while crashing the lamp.
BTW I hope, more of streetlights collectors will make films about their streetlights. For yourself it is normal and not interesting how to open a lantern for example, but for people who never saw them ,it can be very interesting. I am for example very interested to know how to open some old post-top lanterns .