ARRI Forum

Hello! I'm looking at an Arri Amira with 4K license. I'm trying to find a camera that will work for my very specific needs. I had a few questions that I was hoping someone could give me some clarity on.

1. The only specification that I can find for frame rate says that the sensor frame rate is 200fps. Is this accurate for 4K? A lot of cameras, including the Alexa, seem to top out at 60fps for 4K.
2. Can the Amira or any Arri camera shutters be controlled by external trigger? I need to match non-standard frame rates such as 60.0988fps. I would assume the camera will reject a non-standard black burst timing in the way that my Ursa does.
3. I've heard that the Arri cameras allow control of the sensor frame rate down to three decimal places. Is this accurate for the Amira?
4. If the Amira can't be controlled via external trigger, is there any Arri camera which can be?

I need to be able to match the frame rate of some non-standard video resolutions which cannot be frame synchronized. I also require 4K resolution. So far the only camera I've found that could definitely do this is a Phantom camera, but they are far too expensive and I don't need that sort of frame rate, only a little above 60fps.

Thank you for your assistance!

I don't have answers for all the questions, so here's just 2 answers.

1) With a 4K/Premium license, you will get:
HD 1920 x 1080 (interlaced & progressive) 0.75 - 200 fps
2K 2048 x 1152 0.75 - 200 fps
3.2K ProRes 3200 x 1800 0.75 - 60 fps
4K UHD 3840 x 2160 0.75 - 60 fps

Note: ProRes 4444 XQ limits
0.75 - 120 fps HD, 2K
0.75 - 30 fps 4K UHD & 3.2K
Check the AMIRA Brochure for more details https://www.arri.com/en/camera-systems/cameras/amira

3) You can set the sensor frame rate with .000 precision.
https://www.arri.com/en/learn-help/lear ... -simulator

Hi CRTin4K,

I'll fill in...
Where does the 60.0988fps emerge from?

2. You can sync AMIRA with an external source via genlock (see AMIRA Manual, page 104), but I guess non-SMPTE fps might be impossible... Do you have a master clock you can tune to 60.0988? You could try to genlock with that signal. Or you go the other way around: set the camera to 60.098 and use the camera's shutter pulse from the RS-Connector and feed that to your other device.

4. ALEXA 65 might be, Rental has some special tweaks done to it.

Best,
Jan

60.0988fps is the framerate of the NES & SNES. Out of curiosity: Are you trying to sync with video game footage on a CRT?