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The thought of replacing my direct view TV in the Living Room with a projector is becoming a reality. My budget is limited, so i will be buying used. I think 800x600 is the resolution of choice, (higer res == $$$$$$$).


So when looking at projector specs, (and I know that you can't always believe the specs), what would be the lowest lumens to project a decent image of greater then 60" diag from a location about 12 feet from the screen?


Most viewing is at night, so the lighting conditions will be pretty dark, but not movie theater dark. For any viewing durring the day, how much ambiant light is two much?


If anyone has and sub $2000 suggestions, i would love to hear them.


Marc


[This message has been edited by cohnhead (edited 07-03-2001).]
 

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The only sub $2k projectors you would find are all used or B-Stock. The Infocus LP340 streets under $3000 though.


The lumens you will need depend entirely on your screen size and the lighting conditions, distance from the screen is not an issue for brightness. Almost any digital projector will give you a very bright image at 60" diagonal, but the brightness falls of rather quickly as screen size increases because of the increased screen area.


Regards,


Kam Fung
 

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There's a calculation for foot-lamberts floating around the board, as well as a guideline for how many you need under different lighting conditions. Do a little searching, here and in the screens forum if you don't find it. Like Kam said though, if you're going for 60" diagonal, it should be pretty easy. Of course, once you get your PJ, you're gonna want a bigger screen!!!


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Darren Rogers
 

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Marc,


Calculate FtL thusly:


Projector lumens/SqFt of screen * screen gain


Example: 8'x6' screen = 48SqFt, 1500 lumen projector


1500/48=31.25FtL assuming a screen gain of 1...screen gains vary of course, just multiply the resulting figure by the screen gain.


This figure is with a new lamp and assumes the projector will deliver an honest 1500 lumens.


Ideally in a dark theater environment, a brightness level of 14-16 FtL will be fine but as soon as you bring up any room lighting and the ambient light hits the screen, that 14-16FtL target doubles, triples or quadruples in a hurry if you want to be able to have any decent contrast ratio and therefore detail in the shadows. Also, as you can see from the fact that you are dealing with the square footage of the screen, even relatively minor increases or decreases in screen width will have a dramatic effect on the square footage and therefore the brightness of the image...double the width and you end up with only 25% of the original brightness. Hope that clarifies this a bit.


Regards,


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Tom Stites

Director, Business Development

Digital Systems Division

JVC Professional Products

"My opinions do not necessarily reflect..."
 

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Hi Marc,

You might want to consider that the ambient light in the room will determine your (theoretical) absolute black level. In other words, once you get your screen, look at it under the lighing conditions you will use for viewing. That is as dark as your screen will get and since digital projectors don't display a 0 IRE pattern with 0 light transmittance, you will have an even worse absolute black level. However, high contrast can and does help hide this deficiency, since most scenes aren't pitch black. Absolute black level plays a big part in a pictures 3 dimensionality. Some have it, some don't, but in the home theater world, you really can't have too much brightness. My projector's absolute black level sucks, but the brightness can be likened to looking at the face of the sun. http://www.avsforum.com/ubb/biggrin.gif So, it all evens out. Black can look jet black, but dark scenes really show its faults. The only digital projector I've seen with a "wow" type of black level, is the fabled 500 lumen Davis DL450, which I don't think is being made anymore. Beware of some projectors. Yes, they are very bright, but they can also have a humongous light spill (a huge light halo around the periphery of the image - and thus your screen). Their contrast levels are also often exaggerated. I think it's best to lower ambient light as much as possible. You could also do what Milori has done and frame your screen with tiny lights, so you get the illusion of better blacks.
 

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I got rid a huge entertainment center and a 32" Toshiba. Then bought a Sanyo 5500 seen here: http://www.projectorcentral.com/proj...fm?part_id=990 Its 800x600 well 832x624 to be exact, and 500 lumens. Is it the cats meow? No, but it also was only $1,000 used. We added black out shades for each of our windows, and did a DIY screen, and are now figuring out DIY masking. And all I got to say, is wow, for our budget outlay. If I could have found one at our price range, I think the proxima LS1 would have been a better choice, just becuase of a slightly higher out put (700 vs 500 lumnes). But even now, the whites are pretty darn bright in living room. ya blacks could be blacker, but hay it was a crummy $1,000, not the 5,000 or 6,000 some people are spending http://www.avsforum.com/ubb/smile.gif .


Anywho, you have lots of options with your 2,000 budget and looking at used. Oh, and make sure you can either return it, or you can spend lots of time with it before you buy it, I had to return a Eltrohome LCD projector (a telex 400's twin) cause of a blue line going down the middle of it, atleast the guy I bought it from was nice enough about the return. Look for lines, dead pixels, lamp hours, etc.
 
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