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Sony F3 + Sonosax R4 + Lockit acl203 TC drift


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Hi All,

When syncing the audio the picture there is a sync drift of 1 frame each hour. So at the end of an 8 hour day the audio is 8 frames off sync.

I put the lock it on the F3 and connect the timecode + genlock.

Yesterday I brought my R4 + lock it to my dealer and they experienced an sync drift off 1/2 frames each hour. They corrected it but today I got the same problem...

The problem seems the same with different F3 camera's.

We sync in QT/bwf merge.

Anyone experienced something like this?

Sent from my iPhone using Tapatalk

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I'm guessing that your dealer corrected the sync drift between the Lockit and the R4 by retuning the Lockit to the R4's speed with a Master Controller. If so, you could take the Master Controller to your shoot and compare the TC over the course of the day from both the R4 and Lockit to determine if one of them is drifting over a long period. The other thing to check is if the camera is picking up the trilevel sync. Look in the viewfinder while connecting and disconnecting the trilevel sync cable. You should see a glitch in the video as the camera switches sync source from internal to external and vice versa.

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David just checked; We don't see a glitch when connecting the genlock and vice versa. Both bnc cables are fine.

Sent from my iPhone using Tapatalk

Generally you should see the effect of the camera switching to the external sync. If you don't see the glitch then it can be an indication that camera isn't switching to the genlock signal but it's not absolute. I think the Sony does have an external lock indicator but I can't recall if this is timecode or genlock or both. 

 

Another check is to test your BNC-BNC cables with a video monitor rather than a multimeter. Use the BNC video out of the camera to feed a video monitor with the BNC-BNC cables. Multimeters show DC resistance, whereas the Genlock signal is at several MHz. If you can see the video with the BNC-BNC cables then they are truly fine. I test mine with a Lockit and an oscilloscope to check there's a clean & correct level signal. 

 

The Ambient Master Controller is probably your best bet at figuring out which device is drifting by comparing both the TC out of the camera and the TC out of the recorder over a period of time.

 

DM

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