[brotherman]

I am trying to determine just how much does the Optoma H79 benefit from a high power screen.


Right now I have my H79 seating on a pedestal right behind my seating position and over my head, at about 16 feet distance from the screen. The screen is raised (seating on a recliner looking up, the screen’s bottom is about 1 foot above my eye level) and it's a 106†diagonal (16:9). The center of the lens of the H79 is lining up with the bottom of the screen.


I currently have a Da-Lite Da-Mat 1.0 gain permwall (permanent) screen. Removing the frame is not an option so I have to stick with Da-Lite’s screens. Since they are snap-ons, I could get a High Power screen and simply snap it on the existing frame.


Given that there’s a vertical angle between my head and the center of the screen (I’m looking up as I watch from the chair) will I see benefits from the High Power screen? I know the horizontal angle is somewhat limited compared to my current unity gain screen but I am not concerned about that. Is the vertical angle also affected?


Thanks for any advice.

 

[guitarman]

I preferred the mat white to the HP, I've have both. The H79 is too bright of a projector for the screen. Unless you like super bright. My figures say with the MW you're at 14.7ftls if you add say 2.8 gain for the HP you'll be at 36.8ftl. I suppose it wouldn't hurt to own the screen with your setup, you could switch down the road when the bulb ages. At 700hrs the H79 is still blaring bright so far. If I use the HP screen I'll see more artifacts because of the gain.

 

[BJM]

The angle that matters isn't from the center of the screen to your head, it's from your head (or eyes) to the lens. If the lens is only one foot away from your eyes (or even the top of your head) you are within max gain of the HP screen. I agree with Tom that would be way too bright for a 106" diagonal screen.


I also have my H79 about one foot away from the top of my head directly behind me and I did this so I could get a HP screen but I'm planning on 130" diagonal and am planninng on getting a pull down HP and only using it on certain material showing movies mostly on a permanent wall mounted matte white screen.


I guess it just depends on how bright you like it and if you have a totally light controlled room but I wouldn't use a HP screen with the H79 unless you also had a lower gain screen to switch to easily. Nice to be able to do that.


Brent

 

[drapp1952]

I'd go with the High Power and if it is too bright for your taste use a ND filter, but I like the brighter image I get using the H79 & HP and my diagonal is 133". In your setup, which is very good if you want to take advantage of the High Power, the screen will retroflect an image back at the projector. Given you're well within the viewing cone you'll get 2.8 gain at least (as Brent just pointed out while I was typing this). Of course, if you have viewers off axis by more than 30 degrees or so they'll see a much less bright picture.


One could argue that a 1.3-1.5 gain screen without the limited viewing cone would be better, especially if you tend to have a lot of viewers who can't all sit within that cone. But if you long for brightness using your current 1 gain, get the High Power.


Dan

 

[brotherman]

Thanks for the replies everybody. Since the screen is a snap-on, I could just swap between the HP and Da-Mat as needed! I thought about the 1.5 gain but I don't know if it's worth going from 1 to 1.5 gain. Horizontal viewing cone is not an issue and I do like the idea of an ND filter if necessary (easy to remove I assume?). Which ND filter is reccomended for the H79?