Panasonic Varicam at 50fps, what happens to the sound?

[Rainier Davenport]

I just did a commercial shot on a Panasonic Varicam at 25 and 50 fps. All the action was shot at 50fps and the dialogue at 25fps. I recorded some of the action sequences (double system) but left the radio link on the camera. What happens to the sound on the camera at 50fps? Does it record sound and playback at half the speed?

[Ian Thomson]

I'm certainly not an authority on the varicam (only been on a few shoots with it), but from my understanding - the camera is always recording 60fps and recording sound.
For 25fps playback - the audio is engaged/accessable
for 50 fps playback (frame-rate conversion through a deck) - the audio is not accessable.

I'd be happy to find out the truth though.

Ian

[Stuart Waller]

Good question. We did some stuff like this on False Witness except it was all for slow mo stuff. It was really MOS but rolled anyway.

Without testing it I would say yes to your questions. I would playback slower. I know that they can pull the picture back from 50fps by just taking out frames.

I see no real reason to film dialogue at 50fps. Sound should always be at 25fps.

[Rainier Davenport]

None of the dialogue was recorded at 50fps, action only. I forgot about the radio link and it was still putting sound into the camera at 50fps, hence the question.

[Ross Collier]

Varicams are werid in how they operator. As Ian said they are always running at 60fps and you tell it what frame rate you want and its tags those frames for recording. If its running at frame rates that are not normal playback rates then no sound will be recorded, that's something to bear in mind if your feeding the camera audio time code and can be a nightmare with the AG-HVX200A as there is no Timecode or Ref sync in.

With the tape based Varicams they can't playback the different frame rates on a deck, though P2 Varicams will play back Variable frame rates on they're respected devices. The frame rate conversion is done through software or with the new versions of Avid MC and FCP they can detect Varicam footage by a tag that's put into the meta data.

One idea for sync sound (action noises) for slow mo shots that was discussed on the IBSNET was to record the sound for 50fps at 96khz and slow it down to 48khz in post.

I hope that give you a better idea of what they're like.

Ross