How can i set camera exposure to accurate 18%？

[YaoDaDi666]

Hello，i use this tool for icvfx color calibration many times but never get good result.i use novastar led processor which support PQ,and redRaptor 8k vv camera.First i generate the pathch from openvpcal then i play the dpx sequence on led screen use pr,i got the video from red camera ,finnaly i use davince to convert the red video to exr sequence,but every time i got some error and sometime its diffrent.do you have discord or facebook grroup,where can i communicate with other openvpcal user,thanks

[YaoDaDi666]

[YaoDaDi666]

[YaoDaDi666]

[YaoDaDi666]

[giardiello]

hello @YaoDaDi666 , happy to support. If your pipeline is in PQ, you should select ST 2084 in the dropdown menu of the target EOTF.

[YaoDaDi666]

hello @YaoDaDi666 , happy to support. If your pipeline is in PQ, you should select ST 2084 in the dropdown menu of the target EOTF.

thanks for your support,the camera record is set prores4444xq uhd RAW/Log3G10,then i input the video on Davince to convert it as exr sequence,is the workflow is right?

[whatanamesocool]

First of all you must check if your OpenVPCal patch is generated correctly. If you are trying to calibrate your LED set Rec.2020 PQ(ST2084) Or P3 PQ(ST2084) you have to check whats the max brightness of your LED wall. You can simply check it by pulling up your LED wall nits and double check using color meter if you have one. Then, Generate your OpenVPCal patch following your LED wall color space, gamma and nits.
Set your LED at Max Bright and adjust gamma (I’m currently using Brampton Processor and it’s able to adjust gamma 2.2, 2.4, 2.6….. apart from color space and color gamma setting). For the first try you can set it to default. You will see grey steps in OpenVpCal Patch at the very first frame underneath the huge square 18%grey box and check the max white of the grey step is actually hitting the max bright you set in your LED processor If you have a color meter, and if the max white is not bright as much as you set, that’s fine. Check the 18% grey is actually 18% of nits of your max white. So for example if your max white is hitting 1837nits then your 18%grey should be around 330nits.
Try calibrate when these are all set

[YaoDaDi666]

First of all you must check if your OpenVPCal patch is generated correctly. If you are trying to calibrate your LED set Rec.2020 PQ(ST2084) Or P3 PQ(ST2084) you have to check whats the max brightness of your LED wall. You can simply check it by pulling up your LED wall nits and double check using color meter if you have one. Then, Generate your OpenVPCal patch following your LED wall color space, gamma and nits. Set your LED at Max Bright and adjust gamma (I’m currently using Brampton Processor and it’s able to adjust gamma 2.2, 2.4, 2.6….. apart from color space and color gamma setting). For the first try you can set it to default. You will see grey steps in OpenVpCal Patch at the very first frame underneath the huge square 18%grey box and check the max white of the grey step is actually hitting the max bright you set in your LED processor If you have a color meter, and if the max white is not bright as much as you set, that’s fine. Check the 18% grey is actually 18% of nits of your max white. So for example if your max white is hitting 1837nits then your 18%grey should be around 330nits. Try calibrate when these are all set

Sorry we dont have color meter,so we only can read the Led Max Bright from nova led processor,ant it was 1322nit,and the led processor is use p3 and gamma 2.4