Well, as you can see, in 4K view, pixels are not too damaged by the sampling, I think because in 3x crop mod, it's the true 1080p resolution from the middle of the sensor, but maybe i'm wrong ?
I only upscale in export with Resolve 12.5.
This could be interesting for my futurs productions, if clients insist for 4K.
cheers
Made with 5D mk III + Tokina 11 - 16mm 2.8