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Ambient Lockit AC203 and RED camera.


edwar64896

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Gentle sound folk.

Am recording iso tracks on 788T at 25ND/48kHz. I have an  ACL203 jammed to the 788T sitting on the side of the RED with Genlock and Timecode connected.

ACL203 Settings are HD1080P, 25ND, 48kHz - switch settings 3,2,2

RED is set to jamsynch from the ACL203 and to use external genlock (from the ACL203)

Initially, on boot, everything is fine. Chainlink symbol for TC Jam and Padlock symbol for genlock. All Good.

Then, without warning, after a few hours of operation, the RED loses Genlock.

A reboot of the RED solves this problem, but then it appears again.

After a while, rebooting the RED is moot and the genlock simply does not lock.

New cables go to the ACL203 along with new batteries. All in vain.

Suspect that tomorrow, after a cool-down and a good nights sleep, the RED will work fine for a few hours.

Of course the camera department are looking at the sound department and wondering...

My questions to you, gentle sound folk, are...

1. are there any tips/tricks to stabilise the genlock on the RED?

2. Am I doing anything wrong here?

3. what is the likely effect of losing genlock or having an intermittent genlock on the RED?

This is the first time I have seen this happen. Not sure if it is an ACL203 problem or a RED problem, but am assuming the latter.

Mark

Greenside Productions

www.greensideproductions.com.au

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Don't use genlock. RED has enough issues without extra stuff plugged in. TC is written at beginning of file. Genlock is used to sync phase on multiple cameras for 3D. I see no reason for it in any other application.

This is why I have camera house set up box, then jam the box ON the camera or on the camera cart.  I never want it to be on or near my carts.  I treat it as a piece of camera gear. It eliminates the perception of it being a sound problem.

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I'm going to agree with the group as long as your rolls are not long.  I've been involved with the syncing and post of multiple cameras on shoots and if you are going need to roll for more then 20 minutes or so, or if you are using a camera that resolves the TC to it's clock (Sony F900 or Betacam) then genlock. Otherwise, don't do it. It's not worth the potential headache.

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  • 2 weeks later...

I do not agree that the RED does not need genlock, esp for longer takes.  The camera's clock is just too inaccurate to maintain longterm sync w/o TriLevel in sync w/ TC being fed to it.  I've used both Lockits and SBTs with this and have not had genlock issues unless the batteries in the box died.  Are you sure your Ambient box is ok?  I too would tend to suspect the RED first, given its history, but how much do you know about the past life of the Lockit?  Like--is it yours, is it a rental, when was the last time it was checked by a service tech etc?  Are you doing long takes? 

phil p

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I do not agree that the RED does not need genlock, esp for longer takes.  The camera's clock is just too inaccurate to maintain longterm sync w/o TriLevel in sync w/ TC being fed to it.  I've used both Lockits and SBTs with this and have not had genlock issues unless the batteries in the box died.  Are you sure your Ambient box is ok?  I too would tend to suspect the RED first, given its history, but how much do you know about the past life of the Lockit?  Like--is it yours, is it a rental, when was the last time it was checked by a service tech etc?  Are you doing long takes? 

phil p

If the RED camera clock were to drift a frame or two in either direction over a long period of time, I don't see this as an issue, particularly in any narrative of documentary format where edits will occur.  Even in concert footage, edits exist which can easily compensate for any drift of a frame or two or three, which is really all we are talking about here.  I mean, honestly, when was the last time you saw any shot lasting more than a minute or two, even on industrial or educational videos?  And if you did, you'd be too bored to care about a frame or two of drift in and out.

The RED will not try to "correct" itself and resolve to TC, causing the ever elusive and mythical green flash reported in linear tape cameras.

The RED is notoriously jumpy, so why bother pissing it off with more things plugged in to confuse it?  Many folks here have taken to jamming the RED and not even putting a TC box on the camera at all, since most shows will hot-swap batteries and not power down.  Nobody wants to see the dreaded "initializing" show up on the monitors.

Just my opinion,

Robert

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I've found that the red I work with most often drifts about 1-3 frames an hour from both my 788T, and Ambient lockits (which are both tuned periodically to my ACC501). That's way too much to just jam to twice a day. As far as rolling for 10 minutes at a time or less, I'm pretty sure it wouldn't be noticeable. However, this is just this particular camera I see often. YMMV

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If the RED camera clock were to drift a frame or two in either direction over a long period of time, I don't see this as an issue, particularly in any narrative of documentary format where edits will occur.  Even in concert footage, edits exist which can easily compensate for any drift of a frame or two or three, which is really all we are talking about here.  I mean, honestly, when was the last time you saw any shot lasting more than a minute or two, even on industrial or educational videos?  And if you did, you'd be too bored to care about a frame or two of drift in and out.

The RED will not try to "correct" itself and resolve to TC, causing the ever elusive and mythical green flash reported in linear tape cameras.

The RED is notoriously jumpy, so why bother pissing it off with more things plugged in to confuse it?  Many folks here have taken to jamming the RED and not even putting a TC box on the camera at all, since most shows will hot-swap batteries and not power down.  Nobody wants to see the dreaded "initializing" show up on the monitors.

Just my opinion,

Robert

Virtually all RED shoots I work on have takes considerably longer than a minute or two (like 30+ minutes if not longer), and they generally have more than one RED shooting at once.  Not only will the camera not hold sync with my recorder without external clocking, they will not stay in sync with each other either.  This IS an issue in editorial.  Yes, it can be fixed.  Does editorial need more work to do?  Not really.  Is it a good idea to have them constantly questioning the sync of shots as they cut when we could avoid that with the addition of a single cable?  I don't think so.  Why not lock the sync of the funky cameras down if you can? 

phil p

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