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Time code arri alexa mini LF


jfino

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Hi, 

I'm about to work on a project that requires syncing the audio devices mix pre 10 to the Arri alexa mini LF. 

 

Question 1:

Do I need a time code generator or will plugging the mix pre to the Arri be enough to sync up/jamm the time codes? 

 

Question 2

From what I read. Once synced they can stay in sync for 8 hours. 

If batteries are changed on the Arri or the mix pre. Do time codes need to be re synched? 

 

 

We will be using 2 cameras. 

 

Very new to time code and arri Any advice would help. 

 

Thank you so much!

 

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In theory, you should be able to jam the alexa lf from a mixpre 10 tc out connector, assuming you have a bnc -> 5p lemo cable.

 

However, that's a relatively clumsy procedure and camera timecode is not always reliable. And you're right, battery changes would likely throw off the camera as well.

 

Therefore, standard practice is to have a timecode generator feeding every camera. I also have a 3rd timecode box in my bag, feeding my mixer, just to make sure everything is 100% in sync.

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If you are unfamiliar with Arri camera timecode, best be aware of the following. There are two TC Mode options available in recent model Arri's for "jamming" to external TC: "Regen" and "Jam Sync". In both cases you want the "Run Mode" to be "Free Run". While the wider industry uses the term 'jam' to mean either connecting the recorder once, or leaving a TC box on the camera - in the Arri world, this is not the case and causes confusion

 

If you want to connect TC from your MixPre at the start of the day, and I'd suggest at the end of Lunch Break, and 'jam' the camera's internal TC Generator to that - then select "Jam Sync" TC mode. In Arri cameras - this means sampling the incoming TC for around 30sec (sometimes longer) to accurately 'tune' the internal generator to the external source. After that time, it carries on using the Internal generator ONLY. You can disconnect the MixPre. In theory, Arri claim that this 'tune' will hold across battery changes and going off-speed, but I'm not convinced - especially for lunch-break type lengths of power off.

 

If however you want to use an external TC box attached to the camera all the time (more common in professional practice) - choose the "Regen" TC Mode, as it's continuously referencing the external TC source each time a camera file is started.

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+1 on keeping TC locked with whatever TC box on the camera.

I find it also important to mention that you should check the TC sockets of the camera, especially when unfamiliar with Arri. It's basically a little different with every model and with the Mini LF you might get into trouble with a straight Lemo plug because usually they rig the battery for the camera pretty close to the end of the body so there isn't much space for a cable to stick out at the end. It's worse with the Mini then with the Mini LF where the socket is a little "deeper" into the body.

But unless you want to annoy the AC it's best to ask for the right connector (at a rental house) which then has an angled plug in the right direction. They should know if you ask for the specific model.

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On 6/10/2022 at 2:00 PM, Sebi said:

Mini LF you might get into trouble with a straight Lemo plug because usually they rig the battery for the camera pretty close to the end of the body so there isn't much space for a cable to stick out at the end


Actually, on my current project with the Mini LF they specifically asked me to provide a straight Lemo instead of the angled one.

But this does confirm the practice to always speak to the camera dept beforehand and ask them for their preference 

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13 hours ago, Constantin said:


Actually, on my current project with the Mini LF they specifically asked me to provide a straight Lemo instead of the angled one.

But this does confirm the practice to always speak to the camera dept beforehand and ask them for their preference 

That's good to know that the "deeper" sockets of the LF work fine with a straight cable. I only worked with the Mini so far with the TC socket being at the very end of the body so it seems like Arri adressed the problem with the LF I guess.

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  • 5 months later...

Arri claims their time code is accurate to one frame per 8 hours. I have an Ultrasync One time code box and left it running for 27 hours  and it's slow by roughly 90 seconds or 2160 frames over 24 hours at a 24 fps frame rate. I'm going to test all my devices that have internal time code generators next.

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