Screen aspect ratio = tan(FOVh/2) / tan(FOVv/2)
The way things have a way of becoming misunderstood, I wanted to make it clear
that we don't actually want screens which fill up our field of view. As we
already discussed, beyond a certain point, that creates motion sickness. I
suppose that with material filmed specifically for really huge screens, you can
avoid the nausea, but that would be a special case. In general, might not be
good to depend on such special content exclusively.
So, the example of providing a 160 degree by 90 degree FOV was meant to
illustrate, more or less, what human vision expects to see. And if that scene
were to be provided on a screen, its aspect ratio would be very wide indeed,
5.67:1. Which is why wide aspect ratios are more appealing than square ones,
for movies and TV fare, or windshields in cars. It gives us the impression that
we are seeing more of what's out there.
Best I can tell, in practice, you don't want much more than 50 degrees of FOVh,
for movies and TV stuff. And to retain that more pleasant wide screen look, and
avoid providing way more "vertical fill" of your FOV than "horizontal fill," my
guess is that maybe 20 degrees of vertical and 40 degrees of horizontal FOV
would be a reasonably big home screen, and maybe 30 degrees of vertical and 50
degrees of horizontal would be the maximum practical. Just a guess, which fits
what I've read about the motion sickness issue.
With those two data points, these would be two aspect ratios that would work
well:
40 deg h and 20 deg v = aspect ratio 2.06
50 deg h and 30 deg v = aspect ratio 1.74
To me, a single standard of 2:1 would have been nice, and would have worked
better with movie standards. But 1.77:1 isn't a bad choice either.
Bert
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