Herbert Verdino Posted May 21, 2014 Report Share Posted May 21, 2014 Hi. I am actually shooting with an Red Epic and I am using an Ambient ACL 204 to timecode sync it with my Cantar. We are shooting interviews, so the takes we make are 20-30 min. long. I spoke with Ambient and they recommended me, to use Genlock, because of the long clips, we are recording. When we start to record, everything is working well. Both, the TC and Genlock sign on the Epic screen appear in green, showing, that both is ok. But after a while, maybe one hour or 20 min shooting, the Genlock sign jumps to red. So something must be wrong. After a restart of the Epic, everything is fine again, for a while. The Settings on the ACL are 1080p (I tried also 720p) 24F. Also the Epic is set to 24F and it is set to use the external TC. Any Idea, how to fix my Problem? Quote Link to comment Share on other sites More sharing options...
studiomprd Posted May 21, 2014 Report Share Posted May 21, 2014 HV: " Any Idea, how to fix my Problem? " did you go over everything in the recent discussion thread about RED Epic's and Genlock ?? I'm thinking this is a RED Epic issue, maybe ? Quote Link to comment Share on other sites More sharing options...
al mcguire Posted May 21, 2014 Report Share Posted May 21, 2014 Mike this could be a helpful post if you could include the link that you are referring to as this is a difficult site to search. That is if you wish to be helpful. Quote Link to comment Share on other sites More sharing options...
Herbert Verdino Posted May 21, 2014 Author Report Share Posted May 21, 2014 I just spoce with some camera guys and they recomendet me to change the frame rate from 24F to 23.976F could help. Will try this... Quote Link to comment Share on other sites More sharing options...
edward chick Posted May 21, 2014 Report Share Posted May 21, 2014 Hi Herbert. FWIW, I've been on a doc with the RED EPICs and have been using my Ambient Tiny Lockit Sync Box which is just for timecode and we've been shooting long takes like you have mentioned and there have been no problems with sync. Curious as to why they (Ambient) suggested using Genlock? We've been using 23.976 as the frame rate. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted May 21, 2014 Report Share Posted May 21, 2014 HV: " they recomendet me to change the frame rate from 24F to 23.976F " did they say why ?? are they shooting at 24.000 or at 23.976 ?? in either case you need to match them, that's pretty much it... and: 23.976F ?? Quote Link to comment Share on other sites More sharing options...
Masaki Hatsui Posted May 21, 2014 Report Share Posted May 21, 2014 Here's the link to the discussion I started. After struggled with several issues encountered with this camera, we found the way to see GREEN GEN sign but after half hour of shooting, the very same thing happens, the camera lost the sync signal. We abondoned using GenLock for that reason. But it was reported that in some situation there's some weird sync problem occured (which was shot ith another sound guy ho has a Denecke one). In a long shoot the camera seems not keeping it's speed, that it starts synced but there's sync glich in a middle of the way. Which I suppose beacuase of their internal heat problem that it's clock become unstable (my hypothesis). Masaki Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted May 21, 2014 Report Share Posted May 21, 2014 RED Customer Support (949) 206-7900 https://support.red.com/anonymous_requests/new Quote Link to comment Share on other sites More sharing options...
Herbert Verdino Posted May 22, 2014 Author Report Share Posted May 22, 2014 Thank you all for the replies and the links. And thank you Senator for the tip, to select the same frame rate on the cam and on the ACL :-). I think, the reason, why Ambient suggested me to use Genlock was the unstable speed on the Red. Yesterday I did a test run with the Epic set to 23.976 (and the ACL set to the same) and the Genlock sign on the Red kept staying green for at least one and a half houre constant recording! Could be luck also... Quote Link to comment Share on other sites More sharing options...
John Blankenship Posted May 22, 2014 Report Share Posted May 22, 2014 ... Curious as to why they (Ambient) suggested using Genlock? ... Because, contrary to popular misunderstanding, time code does not help a camera maintain sync. Time code simply establishes what frame a camera is on at a specific point in time. With file-based recording, that information is stamped in the file's header when the camera is placed into record. (The same is true of a file-based audio recorder.) From then on, the camera is free running and its speed is determined by its internal crystal. Over time, devices will drift from each other unless a common sync signal (genlock) is supplied to control the speed of each device and lock them frame to frame (think sprocket holes). Time code is not a sync signal but can be used to establish sync at a given point in time, thus the confusion. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted May 22, 2014 Report Share Posted May 22, 2014 (edited) thanks for repeating that somewhat basic, but excellent information again... it is something the camera folks ought to know even better than we ought to Edited May 22, 2014 by studiomprd Quote Link to comment Share on other sites More sharing options...
John Blankenship Posted May 22, 2014 Report Share Posted May 22, 2014 thanks for repeating that somewhat basic, but excellent information again... Glad I could help educate you. <g> Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted May 23, 2014 Report Share Posted May 23, 2014 I have warned people before (especially with toy cameras like DSLRs) that merely sending timecode into the camera will not guarantee proper sync, because the camera has no reference. No reference, no sync. Genlock is a precise reference, and when it dovetails with timecode, you're golden. Quote Link to comment Share on other sites More sharing options...
edward chick Posted May 23, 2014 Report Share Posted May 23, 2014 Thanks for clarifying John. Makes sense. Quote Link to comment Share on other sites More sharing options...
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