Syncing (Genlocking) Arri Alexas from a Tentacle

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As all the current Arri cameras (Alexa, Alexa Mini and Amira) can Genlock or sync from the timecode stream from a lock box, they can of course do so from a Tentacle. For long concert recordings where sync is important to prevent drift, I normally use another brand of lock box for this, and a client of mine is a bit worried about trying it with something so small as a Tentacle. We see a lot of Alexa Minis on hand held or steadicam rigs lately. The camera operators would prefer Tentacles!

I’d like to be able to tell him of people that are using Tentacles to Sync Arris in real life.Is anyone here doing this over longer takes (10min-90min) with success? The only post here I could find about this they were having trouble with green flashes, but I think their Tentacles were on the wrong framerate.


Hi Nick,

many of our costumers do use Tentacles on ARRI Cameras, especially the ALEXA Mini, because its fits so good to the size of the camera 🙂

We have never tried this by ourself how long you can record a take and stay in sync without genlock. But I would say up to 30 minutes it is no problem when using ARRI products.

The other thing I would like to mention is that you can use Timecode as a Genlock Signal for Amira and Alexa Mini Cameras. This works great in general, but we have found out that these cameras do introduce a fixed offset wich is usually 1 frame (for SUP 4.xx).

So I would recommend to use the following settings inside the Amira:

  • Goto System/Sensor Menu and set Genlock-Sync to TC-In
  • Goto TC/Options Menu and set TC-Offset to +1

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