|Originally posted by saw71
I dont know much about screen or what gain is, same with projectors, i dont know about resolution or interlaced or iscan and other stuff people talk about, all i know is that when i saw the projectors they were showing on a white screen and the sanyo and sharp looked good and by reading the forums i take it that the greyhawk will make the picture quality even better.
Okay, how about a quick summary.
Most projection screens are white, because white is the color that reflects all of the incoming spectrum of light. Now, white screens may have something called "gain" associated with them. Obviously, the screen can't emit more light than it receives. But, what it can do is focus that light. So, some screens are designed to take some of the incoming light that would ordinarily be reflected out to the sides, and focus it instead towards the seats directly in front of the screen. In essence, you trade viewing angle for brightness. The seats off to the side don't get as much light, but the seats up front get more.
There's a number associated with this gain (1.3, 1.5, 1.8) which indicates how much more light you get in front than you would with a screen that doesn't focus light output to the front seats. So, a 1.8 gain screen delivers 1.8x as much light. A screen that doesn't do this magic is called a 1.0 gain screen. If you check out the Stewart web site, there's a page describing each of their materials, and if you click on the "more technical information" links for each material, you can see the graphs showing how much light goes where. In general, a higher-gain screen will have a narrower viewing angle. Stewart's screen materials page is at: http://www.stewartfilm.com/home_cine...theater_3.html
Now, why a GrayHawk? DLP and D-ILA projectors are members of a category called "reflective" projectors -- a bright white light source bounces off of a chip which forms the image, and is focused through optics to the screen. (Alternatives are "transmissive" like LCD or light-emitting devices like CRT). Because the chips aren't perfect in their ability to absorb (or deflect) incoming light, they don't produce pure black. Some of the light still gets out, so blacks are a dark gray. However, these projectors can be quite bright (up to 2000 lumens in some models). So, the GrayHawk is a tradeoff. The gray screen (with a gain of .95) actually absorbs some of the light, making the dark grays even darker and more like black. The extra light output of the projector makes up for the reduced reflectivity.
So, is a GrayHawk well suited to a Sharp 9000? I'm not sure. I've seen the 9000 on both a high-gain white screen and a GrayHawk, and I found the white screen to be better. I didn't find that the GrayHawk improved the 9000 picture that much, and it did make it a bit dimmer.
How could this be? Well, keep in mind that most DLP and D-ILA projectors people have been using to date were designed for presentation purposes -- they were intended to produce a bright picture in a lit room. In this environment, light output is important, but true blacks aren't such a big deal.
On the other hand, I believe that some of the new crop of DLP projectors made specifically for home theater (including the 9000) have made the brightness-versus-contrast tradeoff internally. In fact, Marantz has been quoted on this forum as saying exactly that. The Sharp has (claimed) 1100:1 contrsast, but "only" 800 lumens of light output. So, when I saw the 9000 on the white screen, the picture looked very good. When I saw it on the GrayHawk, it looked very good, and somewhat dimmer. I don't think that the 9000 benefits as much from the GrayHawk as some of the earlier projectors.
|A white screen costs around $1000 where a greyhawk costs around $6000, thats australian dollars so double it to get US dollars.
I believe you mean to say "halve that" to get US dollars. What I was trying to point out in my last posting is that $3000US for a GrayHawk is way out of line in the size you quoted, if you use a fixed wall mount and don't get a perforated screen or variable masking. You should be able to get a fixed, non-perfed GrayHawk for under $1500US, and possibly under $1000 if you shop carefully and the import/export situation doesn't cause trouble.
|I have another question, i know different movies have different ratios, when u play movies that have a 2:35:1, will u still get the black bars on the top and bottom and if u do is there a zoom to get rid of the bars and will it lose picture quailty
You can't really use zoom to get rid of the bars. You'll either distort the picture or lose the sides. What people typically do (if they don't just ignore it) is to use a variable mask system. Basically, you can bring black panels or curtains in from the top and bottom of the screen to hide the portions of the screen that aren't getting image on a 2.35 source. The black material (usually velvet or similar) is amazingly good at absorbing the light, so you get a very nice result. If you plan to watch a significant amount of 4:3, you can also get side masks.
The Stewart web site shows all these options, and Stewart will happily sell you a motorized variable mask, but that really will be expensive -- around $6000US with a non-perforated fixed GrayHawk. I'm intending to build my own, based on a design that my friend used on his screen. I will probably not motorize it at first, so it will be quite inexpensive. It will be designed to allow later motorization.
I hope this was helpful!