In some ways I agree with both of you, but I think I will modify your statements. Really is should not be "the Greyhawk is not suitable for every/many digital projectors", more accurately is could be stated that "the Greyhawk is not suitable for all situations with any digital projector".
I think we all know that screen don't "care" which projector is put on it. If I push a G15 to >12' wide the Greyhawk is definitely not going to give a bright image and should not be used. On the other hand a 10' wide Greyhawk with a G15 will give an excellent image in a light controlled environment (~17 ft-lamberts). On an 8' wide screen this combination would give a pretty acceptable image even in low to moderate ambient light (~30 ft-lamberts).
Shooting 1000 lumens onto a 136" Greyhawk screen *is* quite doable *if* the projector meets its specs and *if* you have reasonable light control. I often wonder where manufacturers come up with their brightness specs, I've seen projectors that are lucky to make half their brightness specs when measured.
If your client was expecting an image as bright as a 27" direct view on a 136" screen with ambient light, he's obviously got his sights set too high. That would require a projector over 2000 lumens, preferable 3000+. Those are not cheap! I like to remind people that we are looking at home *theatre*, the objective is to get an image like what we see in the theatre, that usually gives them a better point of comparison than a direct view television. Tell you client to think of it as a theatre projector made smaller to fit in the home, if he compares his front projection system to a direct view TV he will inevitably be disappointed.
I should say that the Greyhawk is inherently better suited for digital projectors where black level is still an issue (except when you get in to the very high end D-Cinema projectors). It will give you better blacks, better contrast, better colour saturation, and better ambient light rejection. The Greyhawk is the proper choice in situations with ambient light because it will maintain black level much better and won't wash out as easily, but anytime you have ambient light you need *a lot* more lumens no matter what gain screen you use.
If you move to a higher gain, non-grey screen you give up these benefits. That is the trade-off if you want to push the screen size to the limit of what the projector is capable of. On CRT's it is, of course, not the same because they have ample black level but not enough brightness.
Of course, if you made clear to the person at Stewart that this was a 1000 lumen projector shooting onto a 136" screen with ambient light and they still recommended you a Greyhawk I think that was probably a mistake. OTOH, in a light controlled room that would probably provide you with an optimum image within the range of the SMPTE brightness spec.
BTW, at CES there were two demos with the DX-1. One that you could walk into that was showing Toy Story 2, that was not a light controlled room, though, with light spilling in through the doors. Nevertheless, the projector looked decent. The other demo was in a light controlled theatre and they were showing U571, MI2, and some live concert footage. All were very impressive and not at all too dim even on a screen size comparable to what you had. Too bad the Sharp looks like it will beat the DX-1 in almost every way. What a difference 8 months makes!
http://www.avsforum.com/ubb/smile.gif
1.5 gain on a 110" screen is a bit of overkill IMHO. The projector isn't that far below its specs is it?
Regards,
Kam Fung
[This message has been edited by KFung (edited 08-17-2001).]
