Composing images is an important consideration. Painters can choose any canvas size they want. Film and video makers are stuck with only a few aspect ratios: 2.35:1, 1.85:1, 16:9, 4:3 and so on. Aspect ratio is defined as screen width to screen height. The proliferation of smart phone video acquisition has popularized the 9:16 format on social media platforms. If students are using smart phones or other types of consumer cameras, unless their intended distribution outlets are Instagram or Snapchat, they should shoot in a horizontal aspect ratio of 16:9 (landscape) rather than in the vertical aspect ratio (portrait). If video is shot vertically and needs to be conformed to other aspect ratios during editing it results in pillarbox (lots of black on the sides of the image). Encourage students to fill their canvas.
Shooting this way fills the frame.
Shooting this way results in video with lots of black on the sides of the frame.
If you want to maximize production value shoot the way motion pictures cameras have always done it; wide first, tall second. Aspect ratio is an important consideration.
No Film School is a great resource for students. Here’s what they write about aspect ratio. “Using Aspect Ratio Like a Pro: Why Choose One Ratio Over Another?
There’s much argument about the use of vertical video and you can read about it below, but in my opinion the best practice is shoot wide, not tall.