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Jamming Alexa from TS-3


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Ran into a problem last week while jamming the Alexa via Lemo out on my TS-3. I jammed the slate from the Nomad. The camera was getting the timecode and displaying it via the readout, but after a few seconds the TC display would flash a couple times then go back to what I'm assuming was the internal clock. I ended up jamming to camera TC to save time, but wanted to know if this sounds familiar to anyone else.

I didn't attempt to jam directly from the Nomad because of the jitter issue with the Nomad TC. Might have worked fine, but again didn't have time.

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I'm doing this on my iPhone so bare with me.

Very timely topic. I'm on a shoot now with two Alexa's. I jam from my Deva to two Deneke's SB2A's and to two TS 3's. The cameras indicate they are in sync and the on set DMT says they look like they hold TC with the slates.

The problem is when it gets to post for transfer they say we have a 2-3 frame offset. They also say the cameras and slates are in sync but sound is not. It's not a consistant offset or they could deal with it. It varies from 2-3 or sometimes just 1. I am using a Deva V running version 7.46 at 23.98 48K.

Any thoughts? I thought I would go back a couple of versio s on the Deva and see if that would help because it's not the first time I've done 23.98. But when Zaxcom took over the user group they don't seem to post the older software versions anymore.

Thanks.

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I often jam Alexas from a TS-C. apart from the slate display being a second ahead, I have had no sync issues. Last weeks shoot was at 23.976. One thing we do however after jammingf is intentionally set the Alexa back to TC Source: INT not sure if it makes a difference but as the internal TC generator is now jammed from your source it should use the internal clock as reference after jamming.. makes sense i think

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Very timely topic. I'm on a shoot now with two Alexa's. I jam from my Deva to two Deneke's SB2A's and to two TS 3's. The cameras indicate they are in sync and the on set DMT says they look like they hold TC with the slates. The problem is when it gets to post for transfer they say we have a 2-3 frame offset. They also say the cameras and slates are in sync but sound is not. It's not a consistant offset or they could deal with it. It varies from 2-3 or sometimes just 1. I am using a Deva V running version 7.46 at 23.98 48K.

Well, the SB-2A is kind of old, but it's still got the TCXO crystal and should be stable. When was the last time it was aligned and checked by Denecke? If you're using two cameras, I think you're better off using the SB-T, because then they can genlock and slave timecode, which is more accurate. In some cases, you can get timecode phase issues, where it's a few microseconds out, enough that it rolls over to the next number and wreaks havoc. This is a huge issue with 3D shoots, where the frame rate, shutter phase, and timecode phase has to be absolutely identical between two cameras.

I have seen digital cameras be a frame or two out, but it's usually a constant offset all day. To me, this is something the assistant editor should just fix in post by slipping the take and checking the claps. It literally takes an hour for them to manually check 100 takes (per camera), so it's not that big a deal; it's supposed to be part of their job.

Having said that, another possible source of inconsistent drift is power cycling on the Deva. I've seen it lose a frame or two once in awhile, and I've always rejammed after that. I would also consider sending a scratch track to at least one camera, which might help narrow the culprit down.

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Marc:

Sorry it took me so long to get back to you. I was surprised when the rental house sent out the older SB-2A's but thats what we got. I am still getting a 2-3 frame offset but the wierd thing is it's not consistent. It can be early or late. I was fortunate to have Glenn Sanders come to set and we decided after talking to Howy that we would try a factory reset. That didn't help. I am going back to version 7.36 my last working version. I will let you know on Tuesday how Monday's transfers go. If that does not work I'm affraid I will have to try another Deva to see if I'm having trouble with mine. I cant see why I would I just finished a series in late January and had no issues. That was at 30FPS and on 35mm but TC is TC and changing frame rates should not matter.

And John we have followed the jamming instuctions to a "T". Post says they have seen this with Deva's more than other machines. Have you heard of any body else having a problem with 7.46 ?

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" I spent 3 months jamming a pair of Alexa from my TS3 slates. No problems at all.

If it took the jam initially, then did something weird, I'd consider it a camera problem and have them check on it."

Hey Robert, why wasn't a an Ambiant Lockit or Deneke SB-2 not used on the Alexa's your show? just curious.

Kevin~

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Well after two weeks of shooting I think Post and I agree with the Senator "CRAP happens :("

I followed the jamming instructions as described and even left the Denecke"s plugged into the Alexa"s. Same result. After having Glenn on set I contacted Howy and we went back to my last known working software. 7.36 from 7.46 with a factory reset. Same result. I then borrowed a friends V for a day with 7.46 to see if it was my machine having the error. It was marginally better with a 1-2 frame offset but not frame accurate. So I thought I could go into the menu setting and try using the offset function in the TC but because it's not a consistent offset post said not to bother. The dailies are getting done and I have gotten the night transfer guy to stop putting it on the lab report if it's not problem and to stop sending up red flags to those that have no idea what it really means other than to say "We're not in sync". Has any one else using a Deva had this issue? Transfer says they see this more with Zaxcom then other products?

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Perhaps use one of the SB2a as external generator for your Deva and use the other to let camera jam the Alexa. There is no need to leave a TC box on the Alexa camera. It contains one of the most stable clocks in the world.

With slates and cameras holding strong, it's clear where the problem lies. Just do your best to find a solution until you can send in the Deva. Not sure of the guts, but maybe they need to replace your TC/clock circuitry.

Robert

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Well after two weeks of shooting I think Post and I agree with the Senator "CRAP happens :("

I followed the jamming instructions as described and even left the Denecke"s plugged into the Alexa"s. Same result. After having Glenn on set I contacted Howy and we went back to my last known working software. 7.36 from 7.46 with a factory reset. Same result. I then borrowed a friends V for a day with 7.46 to see if it was my machine having the error. It was marginally better with a 1-2 frame offset but not frame accurate. So I thought I could go into the menu setting and try using the offset function in the TC but because it's not a consistent offset post said not to bother. The dailies are getting done and I have gotten the night transfer guy to stop putting it on the lab report if it's not problem and to stop sending up red flags to those that have no idea what it really means other than to say "We're not in sync". Has any one else using a Deva had this issue? Transfer says they see this more with Zaxcom then other products?

let me know if you want to borrow my denecke gr1. I am about to put it on ebay, but will wait to hear from you first.

ao

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