Alexa mini judder when panning at UHD

Fri Jul 27, 2018 9:07 pm

I've got the first job with my Mini. When I want to get a panning shot at 4k UHD 60 p it's have a judder, but when I change to HD there is smooth. Please help. My set is 4K UHD 60p for both project and sensor
steven
 
Posts: 3
Joined: Tue Jul 24, 2018 8:17 am

Re: Alexa mini judder when panning at UHD

Mon Jul 30, 2018 4:21 pm

Hi Steven,

that sounds strange. Did you look at a playback on the camera?
Can you link to the clips and provide more details: What is the shot's content (high contrast?), what's the panning speed?, what light's are you using? I guess youre shooting in ProRes?

Thanks,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
Posts: 297
Joined: Wed Aug 13, 2014 3:15 pm
Location: Munich, Germany

Re: Alexa mini judder when panning at UHD

Mon Aug 06, 2018 5:19 pm

Hi Jan,
I test with both RAW 48fps and Prores 4K Cine 60fps, it's still judder but RAW is less. I use outdoor with one M90 and 2 M40.
The problems is when I test it with Prores HD it has no more judder. I also test with my Sony FS7 at 4K cine, the Sony produce smooth with no judder. The panning speed around 3 s for 60 degree. I also sent the footage to Arri Asia. I see judder both when I playback on camera and I saw both in the EVF and my Sony PVM-A170 monitor. I set Mini at 400 ISO, 180 degree, sensor frame and project frame is same ( 48/48 at RAW and 60/60 at Prores 4K - and also SDI frame rate match )
Please explain to me more
Thank you
steven
 
Posts: 3
Joined: Tue Jul 24, 2018 8:17 am

Re: Alexa mini judder when panning at UHD

Fri Aug 10, 2018 12:50 pm

Dear Steven,

just talking about is impossible in that case, I need to see it :)
Please share a link to your files with digitalworkflow@arri.de

Thanks,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
Posts: 297
Joined: Wed Aug 13, 2014 3:15 pm
Location: Munich, Germany

Re: Alexa mini judder when panning at UHD

Sat Aug 18, 2018 10:58 am

Dear Jan,

I've found out the problem. It's not concern about setting of Mini. It's judder when playback on the Mini with UHD but when I playback again on my Imac Pro with 16gb Vram it's smooth. So maybe the problem is playback directly from Cfast have problem. Do you have the opinion on Sandisk card ? I buy Arri verified Lexar.
One more problem that I found with my monitor Sony PVM-A170 that the monitor can support 48fps when SDI signal is 2K so I cannot match the SDI frame rate when I record RAW with 48fps. Do you have any comment on this ? Please help. Thank you
steven
 
Posts: 3
Joined: Tue Jul 24, 2018 8:17 am

Re: Alexa mini judder when panning at UHD

Mon Aug 20, 2018 3:05 pm

Hey Steven,

Sandisk or Lexar should not show differences.
Do you have judder on in-camera playback?

Playback from CFAST readers might not offer enough bandwidth.

For 48fps monitoring (generally HD or UHD; 2K is not supported) choose MONITORING > SDI 1/2 Format > 422 3G HD.

Best,
Jan
Jan Heugel
Application Engineer
Jan Heugel
 
Posts: 297
Joined: Wed Aug 13, 2014 3:15 pm
Location: Munich, Germany

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