In the documentary “For All Mankind” they have some hi-res cameras in the flame trench to record the rockets firing for one of the Apollo missions. They replay it slo-mo in the film. Incredible sight!
yes i have seen it it is amazing must find it again
I think a FReeper directd me to it, but I forget: On Youtube I saw one of these slo-mo cameras aimed at the hold-downs, and a guy narrated it, which was a lot cooler than it sounds.
It was maybe 30 seconds but took a few minutes to play out.
It was very informative.