Backup Camera screen orientation

My backup camera installed with no issues. I got good video with the camera sitting on my desk. I installed it on my license plate. Here’s where the issue starts.

When my iPhone 8 plus is vertical, it shows the smaller image from the camera. When I turn it horizontal, one of two things will happen. It will either continue to show the small vertical image in the large horizontal frame, or it will go full screen with the backup lines but a blank screen otherwise.

Has anyone experienced this or know what I’m doing wrong? I haven’t changed any settings from the default at this point.