Last month I shot a short film on 35mm, using an Arricam LT and an Arriflex 235. We were shooting at 24 fps. We ran out of time and didn't get everything we wanted so went back this week to do some pick-ups and re-shoots, using the same cameras (which I own). This time though, while the 235 footage is perfect, everything we shot with the Arricam, looks sped up, as if it was shot at 20fps. Sound is out of sync and the whole thin is a bit of disaster. The Arricam was not used between the two shoots and I don't understand what could have happened. Is there a way to test the camera speed before I take it to an Arri technician?