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-   -   TC divergence (https://www.dvinfo.net/forum/sony-xdcam-ex-pro-handhelds/508928-tc-divergence.html)

Bill Ward June 30th, 2012 08:29 AM

TC divergence
 
Spent most of last week on a two camera shoot, using an XDCam as the primary camera, and an EX-3 as the 2nd unit. Most of the interviews, we jam synced the TC between the two cameras with a BNC cable left in place during the interview, which worked fine.

I was surprised, though, so see how fast the TC swam apart between the two units when not cabled together--often coming seconds apart from each other in just an hour or two...and 15+ seconds apart overnight while on free run.

I didn't expect a total lock...but that's a lot of TC drift. The EX-3 was largely running faster, if I recall.

Dave Sperling June 30th, 2012 03:11 PM

Re: TC divergence
 
Seems like quite a bit of difference.
Were both cameras constantly powered and on during the period that this much drift occurred? Typically if running on battery power we plan to re-jam time code every time a battery is changed, since most cameras drift when disconnected from power, and many drift as well when powered down.

John DuMontelle June 30th, 2012 07:18 PM

Re: TC divergence
 
Did both cameras have the same drop-frame time code setting? Cabled together for the entire time You were shooting would force them to be the same. However, if one camera had it's time-code set to "drop-frame" and the other camera's time-code was set to "no drop-frame" you would get the problem you describe. If you disconnect the cable from both cameras after the initial jam-synch...they would drift apart over the time periods you describe and that would explain the difference as well.

Doug Jensen July 2nd, 2012 05:36 AM

Re: TC divergence
 
It's also recommended that you genlock them if you want perfect sync.

Bill Ward July 3rd, 2012 09:21 AM

Re: TC divergence
 
Hmmmm....drop/non drop might be an issue.

On the EX-3 if you shoot progressive, the DF is a disabled choice. But the XDCam disc camera was still set to DF...so that is likely what was happening.

Funny part is that for some reason, I was under the impression that progressive was always non drop. I should probably know these things...

Dave Sperling July 3rd, 2012 11:57 AM

Re: TC divergence
 
I thought that 24P was always non-drop, whereas 30p could be either...
The time differential should be a factor of about .001 (if I remember correctly) if that was the issue.

Bill Ward July 3rd, 2012 07:17 PM

Re: TC divergence
 
Well, then, if so even more curious, since we were shooting 24p. Go figure.


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