Originally Posted by reckless7
What is the max size achievable using a home theater projector?
Most projectors can focus out to the size of a drive-in or more, so the main limiter is brightness.
In a dark enough space, brightness is a fairly individual thing as long as dark details are visible enough to not strain the eyes. The standard peak-white brightness that theaters aim for is usually between 12-16 ftL which means the number of measured lumens divided by the square-footage of the screen should equal about 14. If the surface has shine/gain to it or a darker than white negative gain, you multiply the ftl by that peak-gain number to get the most accurate result.
For instance..the w1070 puts out around 1400lumens, and I have a 300" wall which means a 16:9 image of 22ft wide by 12ft tall..so a 264ft-square image. So I divide 1400lm by 264 and get 5.3ftL. My wall is actually a very light grey and not white, so I'm really working with a below 1gain surface..more likely .7gain which means I multiply 5.3ftL by 0.7gain and am really only getting 3.7ftL.
That's about 1/3 as bright as a theater.
Here's where it gets individual, 3.7ftL in a dark space means the w1070's darks will be around 0.002ftL which is still well above the 0.00087ftL point where everything looks pitch-black, so there's still plenty of light left for comfortable shadow detail without raising your brightness..but many do not care for an image this dim. I personally enjoy it and haven't had anyone complain (in fact it's the opposite where the brightness has been commented on positively) which goes to show that people will have different preferences.
The biggest thing I'd recommend if you're playing with a large image, is to make sure you have a gamma control that you can nudge brighter if you feel like you're squinting at dark scenes. Just a little goes a long way and it won't ruin your black floor like turning brightness up.