ARRI Forum

Dear Alexa forum,

I will be shooting a scene with an old CRT monitor (taken from an Philips X-ray machine, looks like from the 80s maybe). I will use an Arri Alexa Plus Classic and the film is generally shot in 24.000fps.
We are planning to replace the content of the screen in VFX but still, I would like to use the screen as a light source, to realistically emulate the light coming from it. The CRT should be PAL and the electricity supply network is on 50hz.
Now I am wondering if in order to prevent any flicker I should arrange a sync / phase control box like the Arri ESU-1. Do you know if such a thing exists for the Alexa, too? Do you think it’ll be necessary?
I’ll do a test with the camera and the screen at the rental probably at the beginning of next week and know more, but I’d like to be prepared (maybe I could arrange such a sync box before the test).

Kind regards, Tilmann

Dear Tilman,

"a bit late" but here's the answer to your question:
the ESU-1 is for film cameras only hence it will not work with ALEXA.

Alexa has the option to define a user button for "phase sensor":

This function temporarily shifts the sensor frame rate for 0.2 fps as long as the user button is pressed in order to adjust the phase of the ALEXA frame rate to an external de- vice, i.e. a CRT monitor or a rear screen projector.
Only available in standby and with time- code in rec run

Which should do the trick.

Cheers,
Jan

Hello,

I came across this post as I am in the process of trying to synchronise an Arri 416 or Arri SR3 with an OLED monitor.

I intend to shoot the OLED monitor, which will show a video I shot on an Alexa Mini. I will directly shoot the monitor with the
16mm camera, and then get that processed to give my digital shot film a 16mm grainy look.

Initial tests look good but there is a wave pattern due to the camera & monitor not being synced. Please see this link for that test:
https://vimeo.com/manage/videos/878227566

My inital thoughts to synchronise the 16mm camera and the OLED monitor are as follows:

-Output a HDMI signal from a PC or Mac
-Input that signal into a Blackmagic UltraStudio 4k Extreme 3
-Output a HD-SDI signal to the OLED monitor
-Also output a composite signal
-Take the Composite signal and input to an Arri ESU-1 or a cinematography electronics Film/Video Synchronisation control
-Connect the ESU-1/Or Film/Video sync control to the Arri 416 or Arri SR3
-Run the camera at 25fps, and run the monitor at 50hz

I have also attached a diagram to make this clearer.

I would be keen to hear any thoughts/advice

Thanks

Owen