Multi-camera sync question

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msk7

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Multi-camera sync question

PostMon Mar 25, 2013 5:57 pm

Hi,
Had anyone tested several BMCCs in long duration multicamera recording?
I want to be sure there's no sync drift problem.
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Margus Voll

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Re: Multi-camera sync question

PostMon Mar 25, 2013 6:37 pm

Hi.

Feed TC to one audio channel and later read the same audio channel for timecode and there should not be any
shift in theory ?
Margus Voll, CSI

http://www.iconstudios.eu
margus (at) iconstudios.eu
IG: margusvoll
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John Brawley

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Re: Multi-camera sync question

PostMon Mar 25, 2013 9:56 pm

You won't get drift on long takes.

You can use an external TC clock and record audio LTC on one of the audio tracks. Resolve can then use this LTC as the TC field. So can a lot of other edits applications like Avid.

JB.
John Brawley ACS
Cinematographer
Los Angeles
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msk7

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Re: Multi-camera sync question

PostTue Mar 26, 2013 6:28 pm

John Brawley wrote:You won't get drift on long takes.

You can use an external TC clock and record audio LTC on one of the audio tracks. Resolve can then use this LTC as the TC field. So can a lot of other edits applications like Avid.

JB.


Thank you for reply, John. Yes I know I can feed TC or even audio signal for later sync. My the question was not about syncing, but about drift as these cameras don't have external sync input. If internal crystals aren't precise enough you'll get drift regardless of timecode. For example if I use canon DSLR in addition to pro cameras, it drifts some frames within 12 minutes of it's longest take (this means FPS is not exact 25). Also different DSLRs drift differently.
So I ask anyone who has at least two BMCCs to start them, make a sync point, then run record for at least hour, make another sync point and compare files if pieces between sync points are of same length.

Mike

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