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I will be starting a feature film shoot with the Sony F-55. The final delivery will be DCP, but the camera cannot record 24 FPS with the current firmware. It will only do 23.976. Since I'm in Europe, I have always been able in the last 30 years to ignore this silliness of fractional frame rates. But now I need to understand it's implications. The thing I don't understand is why some timecode generators and audio recorders have a separate 23.976 fps setting. We would have a TC generator on the camera, synced to the audio recorder (Sonosax R4) , which records the time of day. Both the audio files and camera files store the time of the first frame. There is no more continuous TC track as there used to be with audio and video tape recorders. Only the first frame's time of day. Audio doesn't have different frame rates. It is (usually) recorded at 48'000 samples per seconds. So any FPS setting in the recorder should make no difference whatsoever to the recorded audio. And audio doesn't even record a timecode at all. What the "bext" and iXML chunks contain are samples since midnight (and the "fmt " chunk contains the samples per second). The timecode itself is calculated afterwards by the software using the file (like Avid, etc.). I understand that at 23.976 FPS, at the end of a shot, the picture's timecode as displayed in the Avid would not match the real world time anymore, drifting by about 1 frame every 42 frames. But as long as the sync is done at the start of the picture, that shouldn't matter. If the picture plays back at the same frame rate at which it was recorded (23.976), and the sound plays back at 48K samples per second, both will stay in sync. So my questions are: When using time of day timecode, what difference does a 23.976 frame rate setting on the TC generator actually do? Of course, the difference between 24/25/30 is relevant to converting fractional seconds of the time of day into "frames". But 23.976 or 24 should make no difference. Both count frames from 0 to 23. What does any sort of frame rate setting actually do on the audio recorder? I guess it would only change the frame number in the TC output, which is fed to the external generator when syncing. As above, 23.976 or 24 should make no difference? Is a separate 24 and 23.976 setting actually only relevant to tape based workflows? Or what have I overlooked or misunderstood? Am I an idiot? (if yes, please be kind and elaborate ...) (Of course, at the end the sound will need to be stretched a little for the DCP since DCP's cannot be 23.976)