Yes. Also image aspect ratio and the relationship between horizontal and vertical is complex. Our eyes themselves move reasonably comfortably 15 degrees in all

Yes. Also image aspect ratio and the relationship between horizontal and vertical is complex. Our eyes themselves move reasonably comfortably 15 degrees in all directions (maybe a little less up), but peripheral vision is greater in width than height and we are used to turning our heads to see objects in horizontal field of view more than vertical.