Quote:
Originally Posted by
jmacdonald801 
The light grey goo claims a gain of 1.4
When you say 2.8 gain... are you talking about the screen? Am I really going to need that much gain in a light controlled environment?
My room is about 26 or more feet long, and about 16 feet wide. Lots of room to go back.
16ft. would put it about a foot or two behind my primary viewing area, which I guess would be ideal.
I'll look into the high power screen.
And about these grey screens... is that mostly for non light controlled rooms, or does that work equally well from someone like me who has a dark room but has a larger screen size in mind than typical?
First, an important point: the High Power is retroflective meaning it reflects light given to it back in the same direction from which is came instead of just scattering that light about the room. The downside of this is that viewers off to the side, or more off the projector-screen axis, don't get as much light as they would with a unity gain white screen. Second, 2.8 to 3 gain is what the High Power will give if the light source is just right above your head and (just about always) behind you. (It's hard to imagine a sane setup that includes the projector installed just above the viewer's head height and
in front of the viewer. A Pearl sitting on a coffee table in front of the viewer is more likely but look at the table below very carefully to see what happens.) Here's a table of viewing angle and associated gain with the High Power:
Off axis (The angle between your eyes and the projector) --- Gain
0 ---------------------------------------------------------------------------- 3.1
5 ---------------------------------------------------------------------------- 2.5
10 --------------------------------------------------------------------------- 2.05
15 (coffee table installation?)------------------------------------------------ 1.4
20 ---------------------------------------------------------------------------- .95
25 ---------------------------------------------------------------------------- .8
30 ---------------------------------------------------------------------------- just above .7
35 ---------------------------------------------------------------------------- just below .7
40 -------------------------------------------------------------------------- -- .65
45 ---------------------------------------------------------------------------- just above .6
50 --------------------------------------------------------------------------- - .6
55 -------------------------------------------------------------------------- -- .58
60 --------------------------------------------------------------------------- - .57
Moral of this table: Do not use the High Power if you have a high ceiling and plan on installing the Pearl or any other <1000 lumen advertised pj hugged to the ceiling.
You do not want to go back too far with the Pearl unless you want contrast over brightness given how those attributes change with zoom used. The Pearl needs to be as close to the screen as possible with the zoom fully maxed to give the brightest image possible of some 700+ lumens at around 10000 CR with autoiris. Check out Jason Turk's review to get more exact numbers.
So, you'd have to have the Pearl on a shelf or hung from a long ceiling mount in order for it to be right behind the viewers and just above head height. Note that some home theater owners don't like the idea of viewers standing up and having their shadow disturbing the projected image on the screen with this setup. I feel this is a small pain for high gain.
Which gets us to your question of whether you'll need 2.8 gain. The Pearl will end up putting out somewhere around 300 lumens at end of bulb life if you use a minimum zoom. Little can be done about a too-dim projector except the use of a higher gain screen or concentrating light by shrinking your image by moving the pj closer to the screen and then moving your chairs closer if you want to maintain your field of view. If you find a pj with an iris too bright you can reduce the aperature of the iris to make it dimmer. You might resort to a dimming neutral density filter. One of the few disadvantages to a bright image is that all the warts of bad sources: pixelation, macroblocking, bad edge enhancement, etc. etc., will be more evident. But, again, you can always make it dimmer.
You don't need a gray screen with the Pearl, IMO, although Stewart and Sony have joined to make their Firehawk SST that can be had for thousands of dollars. They say it is specially made for SXRDs such as the Pearl to provide a really good picture. They say it has some kind of special coating to maximize the benefits of 1080p. The Pearl and the Firehawk SST combo did look very good at CEDIA. But, until proven otherwise, and IMHO, unless you have an environment that will result in a fair amount of extraneous light getting back to the screen, that FH SST will not be worth it. To ramble on about your more typical gray screens and to summarize and simplify, they are generally lower gain and that obviously translates into a less bright overall image. A less bright overall image means less light to your eyes but also less to reflect off light-colored couches and walls and floor and ceiling in your room which then means less light to get back into darker parts of the image on the screen. End result: blacks on the screen look less gray. Grey screens were devised in large part to assist projectors with low contrast and mediocre black levels. The Pearl is not one of those. There is no reason to use anything but a white screen in a light controlled non-reflective environment with a high contrast projector.
Dan
