How did they recover the film showing the separation of the S II stage from the S 1C and the tumbling interstage faring which attached the two stages? The camera which is attached to the S II has a view pointing down showing the sequence, yet by all the information I have come across says the S II was destroyed and not recovered. There was no TDRSS system to relay video in those days and the imagery is of film quality. I have seen no account of a film capsule being released from the stage during the launch. There is also a camera view on top of the S II showing the separation of the S IV B.
The cameras were ejected from the stages and parachuted into the sea. If you watch this video you can see cameras being ejected from stages at exactly 5:00 and 7:42.
There's also a good discussion on Collect Space including a picture of one of the modules after it has been fished out of the ocean.