CheesyCam has posted a procedure to set GH4 clocks from Image App. Select "time of day" for time code. They will stay in sync for a few hours.

http://cheesycam.com/timecode-sync-multiple-panasonic-gh4-cameras-multi-cam-editing-fcpx/

I was using 5 tentacles, 2xGH4's, 4xBMMSC, 1 C300 (jammed with timecode), and a sound devices 10 channel recorder as the master timecode. I split 1 of the tentacles across 2 cameras as they were next to each other.

When you put it all in tentacle sync software, you simply have to hit sync which then gets it to see all the audio/file timecode on all the files. You then select the files specific to each camera and set them to a group number based on the video track you want them to appear in your NLE.

I didn't have any issues with sync at all, and we filmed 3 days for around 10 hours each day. I've done it before as well on another similar setup and all worked flawlessly.

Seriously time savers, would of taken me days to sync this stuff in post.

There is a better way. I use 'tentacle syncs' 1 per camera. If you are in vicinity of other cameras, you can use 1 tentacle and run 3.5mm to each camera, but if far apart, easier to buy a separate tentacle per camera.

I've done 5 multicam shoots with this setup, and works flawlessly.

http://forum.tentaclesync.com/

This is a semi-pro camera at best - there are always going to be workarounds at this price point. @tdbristol - there's an external time code input on the yagh but asfaik there's no genlock in

Hi, doing that will not precisely sync the two cameras - the frames on each pair of cameras will be recorded at up to 1/2 frame time difference. This means that if you have movement being viewed by both cameras, the movement will be up to 1/2 frame time different between the two. (I know this, having done lots of 3D work where sync needs to be ideally within 1 pixel time.) The only way to really sync two cameras is to have genlock in, which the GH4 does not have (although not sure if the YAGH gives this feature, or just timecode in). So it depends upon the use - if you just want the same timecode then fine, but if you really want the cameras synced then the GH4 is not the camera that you need.

@DouglasHorn - ^ what he said! I would also power the cameras from mains as opposed to batteries in attempt to mitigate any drift.

@mrbill - can you help me understand your expertise level with this so I can assess your comments? That's not meant to be a jab, I just don't know where you're coming from. There are certain people on this forum who have great technical knowledge and I suppose the main point of my question was to see if someone like VK or LPowell had a ready-made answer for this question, before I dive into extensive (and possibly expensive) testing.

My own understanding of cameras and TC is fairly high--I just don't know the specs on this camera setup--so I'm looking for a high-level answer.

But to clarify the question on subframe accuracy for TC-jammed cameras. I suppose it comes down to this: Say I've jammed multiple cameras to a single "master clock" -- either real via a YAGH or virtual from the Lumix Link app setting multiple cameras to the same mobile device clock (assuming this is sufficiently accurate--which is one open question), ignoring drift for now (assume sync happens briefly before shooting), then if all cameras are shooting 30P. say, when started, will the cameras shoot their first frame on an even multiple of the frame rate such that when all cameras reach a common timecode (say 1:00:10:00) they will be capturing the same moment in time to a resolution of greater than just 33 milliseconds (1/30th) of a second. Will the camera "wait" a few milliseconds after the REC button is pushed until the next frame comes around (which would lead to subframe-type sync) or does the camera just start rolling and stamp whatever the closest available approximation of timecode onto the video stream as the frame is written?

@nomad - pro cameras that will accept an external sync reference will have a frame accurate relationship with any other camera being fed the same sync reference, regardless of cable connection

The trick is clap very loud, slowly, and deliberately.

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Thanks for the replies.

I guess I need to look into the spec a little more. My expectation is that a camera using timecode would start recording on an even multiple of the framerate it is shooting. And therefore any cameras jammed to the same master clock would record the same frame at the same time. My use is about getting multiple cameras synched very closely as well as easing post-production synching. Recording LTC on an audio track won't help with the first part and it's pretty kludgy on a camera that has built-in timecode.

I'll have a second GH4 soon, so I guess I'll just have to run some tests.

@DouglasHorn - some edit packages allow you to record t/code on an audio track, and then use that as an auxiliary time code track. As long as you have multiple t/code outputs from a common source, this might be worth looking at. You could also run black & burst syncs to the t/code unit to ensure the time code unit doesn't drift during recording.