This is why filming in the shape you'll post matters: cropping throws away most of the picture. Planning a shot for both shapes means keeping the action in the middle.
Tools / Crop 16:9 to 9:16 calculator
Free tool
Crop 16:9 to 9:16 calculator
How it worksCropping 16:9 to 9:16 keeps a slice about 32% of the original width. Enter your source size to see the exact crop.