Exactly. I installed projection systems in classrooms, theatres and lecture spaces for three years and the minimum classroom system would be 3500 lumens for a 'short throw' projector. Standards at universities were a minumum of 5000 lumens for a visible screen image.
the inverse square law problem isn't different for short-throw projectors (and it seems the person you are responding to was in fact installing short-throw projectors anyway).
short-throw projectors are just normal projectors optimized for very large beam angles, so at the end of the day the brightness out is exactly proportionnal to lumen amount between regular and short-throw projectors, modulo negligible airborne particles loss.
Cheap but not 4k, so not very interesting - big screens need high resolution much more than most TVs.
I've always thought that Apple should sell a premium Apple TV with a 4k laser projector, that would be interesting.
Has DLP gotten any better? I had a rear projection DLP TV. The bulbs are a decent cost, but then your DLP 'micromirrors' start to fail and the cost isn't really worth maintaining. If that's heat related then I guess the LED source is a boon, but I'm still wary.
If you search for 'white dots dlp' you can see examples of output from failing chips. Chips that start doing this seem to have a cascading failure. I replaced one, but eventually the lamps started adding up or the second chip began to fail, I cant recall anymore.
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[ 2.9 ms ] story [ 30.7 ms ] threadshort-throw projectors are just normal projectors optimized for very large beam angles, so at the end of the day the brightness out is exactly proportionnal to lumen amount between regular and short-throw projectors, modulo negligible airborne particles loss.
Not sure how you were able to do so.