100 and gh4

F

Franner

New member
I'm trying to set up a gh4 as a b cam to my panasonic 100 (or vice versa). In basic tests I am having trouble syncing the footage.. there's drift and there are also different frame sizes. I've a panasonic 14-140 on the gh4 and samyang with adapter on panasonic 100.

Is the drift related to different frame rates. How can I match them best. Does anyone use this combination

Sorry this is probably very basic stuff but the shoot is on Saturday, I haven't shot with them together and I'm starting to panic slightly :-)! It's a pretty simple shoot (a conference) so I'm just looking for simplest way to match the cameras up as best I can. The colour matching which I thought would be the most difficult seems to be working out fine.
 
Sounds like a frame rate issue. Also, are you shooting the Gh4 in 1080 or in 4k? There is a different crop factor between the two when you use the GH4 in 1080 I believe.
 
Pay attention to not only 24p or 30p, but also Drop Frame vs. Non-Drop Frame. The drop frame difference will cause sync drift. Quite generally, don't shoot C4K at 24fps, because it is a different frame size ratio than 1080HD and is true 24fps, not 23.976 to which the AF100 defaults... change to UHD (or whatever flavor of 1080) in the 59.97 (or PAL equivalent) frequency.

Now regarding timecode sync... that's a bit of a pain and you'll likely have to settle for "close enough". On other cameras, I had ample luck setting them both to free run and then resetting the time on each simultaneously (one with each hand) or hitting record buttons simultaneously (usually a few frames off, but close). The GH4 actually has a delay from when you hit record to when the timecode begins. I haven't figured out a simple solution around that yet, other than syncing normally via clap or visual cue.
 
Thanks lads. I was shooting in 4k little bobby, I think you're right that's probably part of the issue.

I'll check the drop frame issue and the uhd (I'm PAL) mcbob.

I'm going to sleep on it as it's after midnight here and hope the brain is a bit fresher in the morning to properly look at your suggestions. I haven't even brought the zoom h4n into the equation yet :-)!

Thanks again :-)
 
Dear Franner,

Your AF100 doesn't actually shoot 24p, it shoots 23.976 FPS

Your GH4 in C4K mode shoots 24p, as in real 24 FPS, not 23.976.

There is a .004 FPS difference and likely the primary source of your drift.

Did you use the YAGH base for TC IN?
 
Hi Illya, no unfortunately I don't have the YAGH base.

That sounds like it is the problem. Can I shoot both at 25p do you know. I'll try and fix that up.. 4k/100m/25p should do it?

Thanks for replying
 
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25p is 25.000 fps, so there should be no sync drift due to a frame rate mismatch. In 25p there is also no such thing as drop-frame timecode (then again, there isn't in 24p either).
 
Thanks for the replies everyone - you steadied the ship just in time and shoot went well :-). It was the frame rate. I'll get that upgrade installed Batutta.
 
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