Screen size; Project bars on screens or 2.35:1 ?

I like option 1.


LMAO

Quote:
Originally Posted by psgcdn /forum/post/20829690


My options are:

1. 128 inch (118x50) diagonal 2.35:1. The panny would project black bars above and below the screen when projecting cinemascope, hitting the painted ceiling. Is that a problem? It would be near impossible for the kids to go into the play room through that door by scooting by the screen.

1. 114-inch (105x45) diagonal 2.35:1. Same as before, but this size seems perhaps more reasonable 10 feet away, and we could still use that door with the screen lowered.

1. Get the 105-wide model in 16:9 format (105x59, 120-in diagonal). Lower the screen to the top of the center speaker for 2.35:1 movies leaving some white screen on the roller, and project black on the top part of the screen, leaving some screen above that with nothing projected on it. When watching movies in other format, I get more vertical screen to play with. I could even drop the screen completely for 16:9 format movies, obscuring the tweeter, but mount a second tweeter lower within the center speaker bass bin (switchable between the two).

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Maximum "recommended" size at that distance is about 80" for high-def. Not to say that bigger is a problem, it's just that pixels are much more easily seen above the maximum recommended size. I'm 9-1/2 feet from my 73" DLP and I start to really see the pixels when I sit forward on the couch (like when eating).


That said, I like the smaller of your outlines. The center is closer to eye level and the screen doesn't go all the way to the ceiling. I envision a short black curtain to hide everything above the screen (the wall and the roller).


I think more of my movies are in a narrower format than 2.35:1, so I would have to set mine up for what I use most often. That means I would probably be set up for 1.85:1 with the bottom of the screen at the top edge of the center, then raise the screen for 2.35:1 movies.


Then again, I might be surprised and find I actually have a majority of 2.35:1 movies.


Either way, I like it with the screen more centered and spaced down from the ceiling more.

Thanks!


We went to the movies today for the first time in a year, came back and looked at the tape in the wall and thought that the bigger option wasn't so big after all. But as you say, it is higher on the wall and will get very close to the ceiling. There's also the question of pixel resolution to consider... My wife said she didn't want grain.


Maybe I should start with the upgrade to 65" plasma instead of the projector! LOL

Hey, I went back and did some reading......


There are several "rules" out there for finding optimum viewing distance. Looks like THX says to divide screen size by .84 to acheive their "optimal" distance that creates a 40 degree angle between the viewer and each side of the screen. Some sources use 30 degrees. Others use 1.5-2 times screen size for viewing distance.


You should be able to use your existing TV to help decide. DOn't get me wrong.....most material should be OK at close distances because of the plethora of colors, shapes, and images that make up scenes. It's when there are a lot of solids and static images that the pixels really become noticeable.


Also, don't confuse grainy with being able to see pixels. A lot of movies are intentionally grainy for effect (or because of bad source material/transfers) and can't be changed.


We like sitting about 4-5 feet away during racing or other competitive video games, and the visibility of pixels is not that noticeable because of the action occurring.


Anyway, back to this screen size thing.....according to THX's recommendations, it looks like 100" would be the recommended size for 10 feet away. I guess you could go up or down a few inches from that.


Place yourself so you're viewing the 50" plasma from 60". That should give you an idea of what it will be like at 10 feet from a 100" screen. Keep in mind, though, that the pixels aren't as visible with DLP because of the diamond shape and being overlapped (they're not really overlapped, but "wobulated"........beyond the scope of this discussion).


And actually, I see the projector you're looking at is an LCD. I haven't seen an LCD projector picture, but I think it will have a screen door effect at close distances, like LCD TVs. Some of the DLP projectors don't use wobulation and have rectangle pixels like LCD, except these DLP projectors have a higher fill factor, making the "screen door" less visible.



I should stop now. I think I'm getting over my head.


I still vote for about a 100" screen.



Quote:
Originally Posted by Crabalocker /forum/post/20831634


if your projector is 17-18' back, why are you limited to sitting 10' from the screen?


I don't know, I sat 12' back from my 130" screen and now sit 15' back from my 153" screen....it looks great

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First row is 10' from the screen and the main speaker's sweet spot (for music).

12' back from your 130" screen would be similar to 10' back from a 108" screen. This a diagonal I assume?

Quote:
Originally Posted by the Son /forum/post/20831670


Hey, I went back and did some reading......


There are several "rules" out there for finding optimum viewing distance. Looks like THX says to divide screen size by .84 to acheive their "optimal" distance that creates a 40 degree angle between the viewer and each side of the screen. Some sources use 30 degrees. Others use 1.5-2 times screen size for viewing distance.


You should be able to use your existing TV to help decide. DOn't get me wrong.....most material should be OK at close distances because of the plethora of colors, shapes, and images that make up scenes. It's when there are a lot of solids and static images that the pixels really become noticeable.


Also, don't confuse grainy with being able to see pixels. A lot of movies are intentionally grainy for effect (or because of bad source material/transfers) and can't be changed.


We like sitting about 4-5 feet away during racing or other competitive video games, and the visibility of pixels is not that noticeable because of the action occurring.


Anyway, back to this screen size thing.....according to THX's recommendations, it looks like 100" would be the recommended size for 10 feet away. I guess you could go up or down a few inches from that.


Place yourself so you're viewing the 50" plasma from 60". That should give you an idea of what it will be like at 10 feet from a 100" screen. Keep in mind, though, that the pixels aren't as visible with DLP because of the diamond shape and being overlapped (they're not really overlapped, but "wobulated"........beyond the scope of this discussion).


And actually, I see the projector you're looking at is an LCD. I haven't seen an LCD projector picture, but I think it will have a screen door effect at close distances, like LCD TVs. Some of the DLP projectors don't use wobulation and have rectangle pixels like LCD, except these DLP projectors have a higher fill factor, making the "screen door" less visible.



I should stop now. I think I'm getting over my head.


I still vote for about a 100" screen.

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That's similar to Crabalocker's vote in that I shouldn't go with the larger one.


It's a good point about grain vs pixels, and I hadn't considered that motion can blur pixels. Thanks.

Just looking at the calculator pro from Projector Central and seems with the projector that far back (17'-18') you're only gonna' get 10fl for a 1.0 gain screen, not very good. I would ceiling mount or table mount the projector closer if possible.


I'm by no means an expert I just know what my eyes like. I use an A/T screen so if I get too close I can start seeing the weave so I can't help by seeing how close I can get to my 153" screen. But that being said I can sit 13" back and it still looks OK and my projector is an Epson 8500UB, very similar to the AE4000.


My final advice would be to get the projector, project it on a wall (any wall, not necessarily the wall in that room) at the size you want and see what it looks like 10 feet back. You will be surprised at how good the picture looks even projected on a wall. This way you can get an Idea before you purchase a screen; Just a thought.


You'll love the new projectors, they are absolutely fantastic! you will not be disappointed with the Panasonic projector and what ever screen you go with, even a 100" screen is better than a 65" plasma or LeD.....IMHO. To me, bigger is better that's why I went from 130" to 153", now I'm thinking of getting a 190" 2.35:1 screen (same height as my 153" 16:9 screen). But that will require a light cannon and an anamorphic lens! Runco LS-10 here I come!

Quote:
I'm not a physicist but I know what happens to a projectors light with distance. Please someone chime in who knows the proper terms and science.


a few examples:


I tied this when setting up my own projector and know from first hand experience that this happens, why? f-stop change? light leakage or scattering? but I'm pretty sure it's the inverse-square law, I think.


Just using a projector calculator supports this Idea. With a 100" 1.0 gain screen, and a PT-AE4000 with the projector at 18' the best image brightness shows 10fl. Now if the projector is say at 10 feet the image brightness shows 27fl. The closer the projector is to the screen, yes using the zoom to fill the same size screen, the brighter it is; just as I experienced.


And this from the review on the PT-AE4000U from projector central:

Quote:
I'm not trying to be confrontational but I know this happens from my own experience.


A partial explanation of the inverse-square law:


"The intensity of light or other linear waves radiating from a point source is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period)."


Is this what's causing the loss?


Since this is starting to get argumentative I will say goodbye and good luck with your project, I know you'll love a projector and you'll see for yourself when you do get one (I bet you will end up moving it closer, or getting a high gain screen ).

The zoom lens is causing the loss not the inverse square law. If you were to project on a 100" screen and move the projector back without changing the zoom until you get a 200" screen that is where the inverse square law applies as the 100" screen area wouldn't have as much light hitting it. Many photographers use this formula to arrange their lighting for the desired effect they are trying to achieve.


In theory you lose a little bit of light because of particles in the air but in a room the difference is negligible and I doubt it could even be measured without laboratory instrumentation. It would probably equal a thousandth of a ft/l or something crazy like that.


Now any zoom lens changes the amount of light it lets through between short and long end of the zoom. The larger the zoom range the greater the light difference between the short and long end of it, assuming the same quality optics of course. So many of the projectors that have an ~2.0x zoom range will have a bigger light difference between the short and long end of the throw range compared to a projector with an ~1.2x zoom.

Quote:
Lighting up a 128" 2.35 screen is roughly the same as lighting up a 135" 16:9 screen. You loose all of the lumens in the gray bars. They are not concentrated onto the rest of the screen unless you use an anamorphic lens. Even with a lens you still loose some light. Unless the screen has a lot of gain you are not going to be able to light it up with the AE4000 unless you use dynamic mode and normal lamp, but still not a good choice. A 1.0 gain screen of that size (128" 2.35) is only going to give you around 17.2FL using calibrated dynamic mode, normal lamp (high) and mid zoom (17'-8"). With that size screen you will get very little life out of the lamp. You either need to reduce the size of the screen, increase the gain of the screen, buy a projector with more lumens or a combination of the above. BobL is giving you good advice on the desired lumen output. I see so many people on here that don't start off with a system that has enough lumens. It looks great the first few hundred hours, but after that it is too dim.


As for viewing distance. On a 100" screen the full benefit of 1080P starts around 12.5'. Of course this varies due to eyesight. http://hd.engadget.com/2006/12/09/10...o-screen-size/


Another option to consider is an AT screen. An AT screen would allow you to lower the screen down in front of the center channel, getting the screen away from the ceiling. It would also allow you at some point to remove the TV and raise the center speaker to the correct location if wanted. You still would need to carefully select screen size, gain and projector choice so that you get adequate lumens for your needs.


People that go with real large screens usually have to sacrifice image quality and/or lamp life, usually both. You might want to wait until after cedia. There are a lot of new projectors coming out that will have a lot more lumens than the AE4000. If I can help you in any way, let me know.


Added

I like your speakers. One of the best systems that I have ever heard used modded Klipschorn speakers along with two DTS-10 subwoofers in a well treated room. Don't forget to think about sound treatments for your room. Sound treatments make a huge impact to an HT.

Quote:
Bob,


Great discussion. Are there any projector lenses out there that have a >/=2:1 zoom range and are constant aperture, to allow for no light loss at the long end of the zoom? As compared to a photographic lens, I wouldn't think you need nearly the resolving capabilities for a PJ lens. Modern coatings provide for the macro-level contrast in photo lenses and could be applied, I would think, to PJ lenses. Now I only have a rudimentary and pedestrian understanding of optics, which will probably show in what I'm about to say. But is seems to me that since we so often run into issues with lumen shortage on big screens, unless you pay the big bucks, perhaps the lens would be more cost-effective to address. You could go with a big aperture as long as there is no significant field curvature to the lens, and maintain sharp enough focus on the screen while letting a bunch more light through the lens. I'm probably totally missing something here with regard to the physics. But wouldn't it be nice if PJ manufacturers offered a base lens and a higher quality lens option that passed more light with better contrast throughout it's range?


For instance, the lens on my Epson is a 22.5-47.2mm zoom, and goes from f/2.0 to f/3.17 throughout its range. I don't know how big an image circle this provides from the rear element of the lens to the "image generation plane". But there are camera lenses that go from 17mm-50mm at f/2.8 (3:1 zoom) through the range that cover a 16x24mm sensor that cost as little as $350, and prime lenses as short as 24mm at f/1.4 that cover a 24x36mm sensor (admittedly expensive at around $1500, but with amazing resolution capabilities not needed for projection). Now this is all pie in the sky, but it would be pretty cool to have the option of buying one high-quality lens with optimal characteristics for your room from a manufacturer that could be interchanged when you upgrade your PJ, from the same manufacturer of course. We do this all the time in photography, and I use some lenses made in the '70s as well as modern design depending on application. Image sensor technology changes all the time, but we can continue to take advantage of the optical qualities of well made glass as we upgrade the camera bodies. I'm sure there is a market for this in PJ-land too.

Sorry for the late reply all, I was away on vacation.

Quote:
Originally Posted by Crabalocker /forum/post/20840922


I'm not a physicist but I know what happens to a projectors light with distance.

Click to expand...

I am a physicist and realized that the same area was light up, but didn't think of the aperture change of the lens when zooming. That explains it, thanks.


So I shouldn't mount my projector at the back of the room... too bad. I didn't fancy the look and noise of a projector above my head in the middle of the room.

Quote:
Originally Posted by mjg100 /forum/post/20845590


Lighting up a 128" 2.35 screen is roughly the same as lighting up a 135" 16:9 screen. You loose all of the lumens in the gray bars. They are not concentrated onto the rest of the screen unless you use an anamorphic lens. Even with a lens you still loose some light. Unless the screen has a lot of gain you are not going to be able to light it up with the AE4000 unless you use dynamic mode and normal lamp, but still not a good choice. A 1.0 gain screen of that size (128" 2.35) is only going to give you around 17.2FL using calibrated dynamic mode, normal lamp (high) and mid zoom (17'-8"). With that size screen you will get very little life out of the lamp. You either need to reduce the size of the screen, increase the gain of the screen, buy a projector with more lumens or a combination of the above. BobL is giving you good advice on the desired lumen output. I see so many people on here that don't start off with a system that has enough lumens. It looks great the first few hundred hours, but after that it is too dim.

Click to expand...

Even mounted 10 feet away from the scrren?

Quote:
Originally Posted by mjg100 /forum/post/20845590


Another option to consider is an AT screen. An AT screen would allow you to lower the screen down in front of the center channel, getting the screen away from the ceiling. It would also allow you at some point to remove the TV and raise the center speaker to the correct location if wanted. You still would need to carefully select screen size, gain and projector choice so that you get adequate lumens for your needs.

Click to expand...

AT screens are out of my budget... Also, the center speaker stays there. It's inset two feet into the wall!

Quote:
Originally Posted by mjg100 /forum/post/20845590


People that go with real large screens usually have to sacrifice image quality and/or lamp life, usually both. You might want to wait until after cedia. There are a lot of new projectors coming out that will have a lot more lumens than the AE4000. If I can help you in any way, let me know.

Click to expand...

Thanks, good advice! I just may wait a few months...

Quote:
Originally Posted by mjg100 /forum/post/20845590


Added

I like your speakers. One of the best systems that I have ever heard used modded Klipschorn speakers along with two DTS-10 subwoofers in a well treated room. Don't forget to think about sound treatments for your room. Sound treatments make a huge impact to an HT.

Click to expand...

Thanks. I use a Tuba HT sub and get decent results there. I will investigate room treatment after I measure it again with the drop ceiling installed.

I'm back...


THX theater recommendations says that the minimum screen angle (back row) should be 36 degrees and maximum (front row) 53 degrees. I have 58.5" clearance between the top of my center speaker and the ceiling joists where I can hang an electric screen. The largest 16:9 screen that I can fit that clears the tweeter (barely) is:


106 diagonal 16:9 (92"x52")

Provides 100-inch diagonal 2.35:1 screen (92x39)

Viewing angle of 42.1 degrees


Not too bad. The screen is $1250 and since I would use a fixed setup on the projector (no zoom change), I could get by with an Epson Powerlite Home Cinema 8350 projector.


The extreme I can go is:


135 inch diagonal 16:9 (118x66), except I'd never see it all...

Provides 128 inch diagonal 2.35:1 (118x50)

Viewing angle of 52.2 degrees (close to THX maximum!)


The full height of this larger screen is 72 to 73 inches and blocks the center speaker mid-driver. Therefore, it would never be used this way but would be a cheaper alternative to 2.35:1 version of the same width screen (a custom size). I would simply leave the excess white screen on the roller. I would lower the screen to the center speaker top and project 2.35:1 right up to the edge of the screen-mount, 1 inch below the suspended ceiling. I would project the black bars onto the ceiling a bit, so that might be a con. For 16:9 content, I would need to zoom the projector in to occupy the 50" height, leaving bars on the sides. I'd need a more expensive projector with different automatic lens shift and zoom setting (Panasonic PT-AE7000, $1900). The screen is $1800.


Therefore, HDTV format content would be projected at about the same size on both screens. Widescreen content would be much bigger on the larger screen. The attached picture shows the two sizes.


Pros and cons of the bigger screen:

Pro:

• 64% bigger area than the 106-inch on 2.35:1 content!!

Cons:

• I would never unroll the whole screen (but only I know that, really).
• The image would always be very close to the ceiling (does it matter when it's dark?)
• The 118-inch wide projected image for 2.35:1 is a stretch for the projector (so the image contrast won't be as good).
• At the edge of being too big.
• the bottom bar of the screen is 137 inches and would block the door to the kid's room completely. They would have to push against the screen to get by it if it were lowered (The 106" screen blocks half the door, so they might be able to scoot by).
• $1450 more expensive after taxes.

Wide-and picture taken from the back of the room (makes everything look small):



And from just behind the couch: