Interpolated 4K (2160p) Quality

[canad2006]

The 4K in Git2 is interpolated. So the best real resolution is 2K.
I typically record movies in the highest possible resolution, but render them to 1080p during post production. This allows me to take crops, when needed.

The question is rather technical, so I would appreciate if someone really knows it to answer.
Which one brings more quality? Downscaling from 4K interpolated to 1080p, or from real 2K to 1080p?

 

[What]

Neither. It's actually TRUE 2160p but the actual information captured is not 16x9 wide screen. In reality it is what's called anamorphic. As a result the output video is 2160p which is the same height as 4k, but instead of being 3840X2160 16x9 wide screen, it's 2880X2160, but the width is anamorphic. In this case it means the width is interpolated, but not the height. So it's not true 4K but it's also not true interpolation. It is true 4k height but interpolated width.