Originally posted by e1618978
You are using 30 degree vertical, not horizontal, in your calculations. That is a damn huge screen.
30 degree horizontal (and 15 degree vertical) is what I was talking about (for which 1080p is fine).
Its not fine as that's the worst seat in a theater. More than 50% of the folks prefer to sit closer than the last row of the theater (just by observing where folks sit in a theater). 30 degrees horizontal viewing angle is the minimum found to produce immersion...hence the spec for HDTV.
Also your assumptions are incorrect. Humans can see objects far smaller than 1 arc minute in darkfield situations (ie the night sky). Otherwise we wouldn't be able to see stars. Detection acuity is far higher than the ability to resolve.
Also when you have lines (horizontal or vertical) humans can see (detect) much smaller objects than 1 arc minute as in the aformentioned power lines (yes, they do sag but they aren't diagonal which appears to be harder to see).
While you cannot resolve stars (or planets) or power lines not seeing them will reduce immersion. Seeing these objects, even if you can't resolve them, increases immersion. This perhaps one reason why gigapixel murals appear more life like than lower resolution murals (http://www.gigapxl.org/
This is ignoring that the range for normal human acuity ranges from .7 to 1 arc minutes. 1080p is barely acceptable for home theater.
Sit further away (required by lower resolution or just better eyesight) and you do not get immersion effects. Sit closer and you start to see pixel structure.