The world is horizontal. All viewing devices except cell phones are, and even they are easily held in landscape. Vertical (or “portrait,” this should give you a hint) works well for one thing, and one thing only: to take portraits. Landscape is for landscapes, more than one person, things, people who are standing next to something. As a rule of thumb: if you can zoom in and still have a useful picture or if you have to take more than a step to get to something, use landscape.
There are, of course, aesthetic, reasons. Landscape “looks” better. But aesthetics are debatable1.
What’s not debatable is neurology and medicine in this case: our eyes aren’t made to work well on a surface narrower than nine centimeters (the iPhone 7 has not quite seven, the iPhone 7+ not quite 8cm) when moving content is presented. In the simplest case (you’re young, male, and white2) this leads to a little strain that’s simply glossed over. In the worst case, it can lead to nausea, exacerbation of migraine onset, and worse.
A counter argument is, that some content is simply made to be viewed on cell phones (Instagram and Snapchat do this all the time when asked) and therefore it’s OK to shoot it in an orientation that’s only made for cell phones. That’s a valid consideration, if you neglect the neurological aspects above. But even then, your camera is fully capable of doing both, no matter what kind you use. Yet, only cell phones are good receptacles for the portrait kind, so unless excluding audiences is your goal (everyone can view wide videos), why not hold your camera the way all devices can display, and display well?
Vertical video goes counter to the way we see, counter to the way we (therefore) designed video display devices, and counter to the neurological and anatomical realities in humans. Don’t do it.
- The aesthetics of various formats for film and photography are being debated by scholars since the mid-13th century (then only paintings), when Guiseppe DiNuzzo stabbed his opponent in a debate about canvas sizes with a sharpened paintbrush handle, killing him, and finally attaining the notoriety and fame his 22×6 (hxw) paintings did not afford him.
- Current research shows, that women, Asians, and older viewers have an even wider FoV and depth following at narrower distances and widths. This also plagues VR Headset makers with issues partially and loosely related to vergence accommodation