I need to throw a 100 inch screen from 16 feet or so.
Lumenlab focal length calculator (http://www.lumenlab.com/forums/index.php?showtopic=29)
Numbers I used:
Size of object to be projected in inches (ie. your LCD panel):
15 inches
Distance from projector lens to screen in inches:
197 inches
Size of projected image in inches:
100 inches
Focal length of lens in inches:
results in 25.70 inches.
I need a lens with a 25.70 inch focal length.
The lumen pro lens is 500mm (19.68 inches).
Is there something I can do inside the projector to make this lens throw 16 feet?
Full Version: 100 Inch Horizontal Screen - 16 Foot 5 Inch Throw
QUOTE (PLJack @ Aug 18 2006, 10:45 PM) 
Is there something I can do inside the projector to make this lens throw 16 feet?
Yes, get a smaller diagonal lcd. Or a 22 inch F.L. opaque projector lens.
You're the person who has a shelf over the kitchen sink and you want to project to the opposite wall, which is 17' away right?
I don't want to sound like a broken MP3, but don't forget that the "throw length" is the distance from the projection lens to the screen. The projector is going to be roughly 3ft long, the screen will probably be 6in from the wall, you also may want about 6in from the back of the projector to the wall (possibly for air flow, plugs, leway, etc.). At that point you've got
17' - 3' - 0.5' - 0.5' = 13'
With 13' of throw it would be a lot easier to get the 100" screen that youdesire. Even 15' would probably be considerably easier than 17'...
I don't want to sound like a broken MP3, but don't forget that the "throw length" is the distance from the projection lens to the screen. The projector is going to be roughly 3ft long, the screen will probably be 6in from the wall, you also may want about 6in from the back of the projector to the wall (possibly for air flow, plugs, leway, etc.). At that point you've got
17' - 3' - 0.5' - 0.5' = 13'
With 13' of throw it would be a lot easier to get the 100" screen that youdesire. Even 15' would probably be considerably easier than 17'...
QUOTE (Hirudin @ Aug 18 2006, 07:28 PM)
You're the person who has a shelf over the kitchen sink and you want to project to the opposite wall, which is 17' away right?
Nope, sorry not me.
The room is 18 feet, 6 inches.
My box plan is not yet complete. I need to resolve this question before I can continue with the design.
It will be a vertical fold. Lost likely a 2ft x 2ft box. Hight as yet undetermined.
I'm assuming a projection lens a little over 2 feet from the back wall.
QUOTE (Hirudin @ Aug 18 2006, 07:28 PM)
With 13' of throw it would be a lot easier to get the 100" screen that youdesire. Even 15' would probably be considerably easier than 17'...
Currently I am planing a tall media center with the projector built into the top.
Moving it several feet from the wall will place it in an awkward position within living room.
QUOTE (Mikey P. @ Aug 18 2006, 06:50 PM)
Yes, get a smaller diagonal lcd.
What? I have been reading these forums everyday for weeks now. Obviously I need to read more. I don't follow the smaller screen logic. Plus I was planing on using a 15 inch LCD to build with. Then upgrade to a 17 inch later. Something tells me that plan is in danger as well.
I had hoped to buy 17 inch LCD optics and place a 15 inch in it for now.
QUOTE (Mikey P. @ Aug 18 2006, 06:50 PM)
Or a 22 inch F.L. opaque projector lens.
Not from LumenLab I take it. Are there providers of new ones or is this a "hunt ebay" kind of item.
Thanks both Hirudin and Mikey P for replying.
This is not my first design. I have been all over the map with design types. I would like to settle on a media center (piece of furniture) design. But, not if I can't place it against the back wall.
QUOTE (PLJack @ Aug 18 2006, 07:13 PM)
What? I have been reading these forums everyday for weeks now. Obviously I need to read more. I don't follow the smaller screen logic. Plus I was planing on using a 15 inch LCD to build with. Then upgrade to a 17 inch later. Something tells me that plan is in danger as well.
I had hoped to buy 17 inch LCD optics and place a 15 inch in it for now.
Not from LumenLab I take it. Are there providers of new ones or is this a "hunt ebay" kind of item.
Thanks both Hirudin and Mikey P for replying.
This is not my first design. I have been all over the map with design types. I would like to settle on a media center (piece of furniture) design. But, not if I can't place it against the back wall.
I had hoped to buy 17 inch LCD optics and place a 15 inch in it for now.
Not from LumenLab I take it. Are there providers of new ones or is this a "hunt ebay" kind of item.
Thanks both Hirudin and Mikey P for replying.
This is not my first design. I have been all over the map with design types. I would like to settle on a media center (piece of furniture) design. But, not if I can't place it against the back wall.
Most people use 15" panels because they're cheap. Most go to a 17" because of the added resolution. What Mikey P. is saying is that with a smaller LCD the projected size will also be smaller. Generially small LCDs have low resolution, but there are better ones out there. Check out this possible (but not likely in my opinion) group buy: Optrex 8,4" Xga + Sxga Interface Board Group Buy
You'll also want to check out this thread (this is where I got the kitchen shelf story from).
Source For Long Throw Lenses?
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