Recording video in portrait/9:16

[joaonp]

Hi,

I'm into a project which will record (Sony A7S MK2) and display videos in 9:16. We're having some problem because of the shutter jello effect. It gets stronger when recording in that ''portrait mode''. Does anyone have already recorded that way and/or have a solution for that jello effect? We can't record 60p because they want the footage to be 4K, so it's going to be 30p.