Not long ago there was a thread regarding the film of the stage and ring separation from the Apollo launches. The question was How did they get the film? See the thread here:
After some speculation I contacted spaceline.org to get the straight dope. They were very helpful in finding the information I asked for. According to a NASA media release the film was taken by cameras mounted inside the forward skirt area of the first stage. There were a total of 4 film cameras to record the stage separation as well as the interior of the LOX tank. Quoting from the release
“The capsules, which contain the cameras, are ejected automatically about 25 seconds after separation and are recovered after descent into the water.”
I hope this answers your question Johnny L.A.