Question about projector distance

[LeAnn B]

I don't know how to figure throw distance, etc so I was wondering if someone could tell me...if I had this screen and http://www.newegg.com/Product/Product.aspx?Item=N82E16824009285 how far away does the projector have to be from the screen in order for the image to fill it/be clear etc?

[LeAnn B]

Wow something is up with links, can't get them to post correctly
http://www.newegg.com/Product/Produc...82E16824009285
Amazon.com: 84INX84IN Model B Manual Pull Down...

[tdangelo]

LeAnn,

We are missing some information in the equation. We would need to know what lens is on the projector and what aspect ratio (eg: 4:3, 16:9) you are projecting in.

[LeAnn B]

Looks like the lens is
F = 2.41 ~ 2.55, f = 21.79mm ~ 23.99mm

1:1.1 Manual Zoom and Manual Focus
Throw Ratio: 50"@2m (1.95 ~ 2.15:1)

Whatever that means And probably 4:3 ratio

[prochlea]

Tom - Given that she has a 84"x84" screen, and a projector that's XGA, I think we can assume that she's going to 4:3. Also - I don't think this projector even has optional lenses.

LeAnn -

see this link - Projector Calculator

One thing to note, that with an 84"x84" screen you won't be able to fill it completely, as that is a square screen and an XGA projector has a rectangular image in a 4:3 ratio. With a square screen, you're going to fill the screen left to right, but have empty space at the top or bottom of the screen.

but - based on that calculator, 14' 4" is your optimal location, with about 8" of play forward or backward. I would recommend being as close to that 14'4" distance as possible, so that you have a little bit of cushion using the zoom of the lens. You never want to be on either extreme of the lens, other wise you may not be able to get the image to fit the screen properly.

[LeAnn B]

Ya I checked out that Projector Calculator before I posted here but it made my brain hurt Thanks for the quick response! That's ok if it doesn't fill the screen completely, I understand the ratio vs screen size dilemma, just trying to go ultra-cheap since this is for a church camp. Thanks again!

Originally Posted by prochlea

Tom - Given that she has a 84"x84" screen, and a projector that's XGA, I think we can assume that she's going to 4:3. Also - I don't think this projector even has optional lenses.

LeAnn -

see this link - Projector Calculator

One thing to note, that with an 84"x84" screen you won't be able to fill it completely, as that is a square screen and an XGA projector has a rectangular image in a 4:3 ratio. With a square screen, you're going to fill the screen left to right, but have empty space at the top or bottom of the screen.

but - based on that calculator, 14' 4" is your optimal location, with about 8" of play forward or backward. I would recommend being as close to that 14'4" distance as possible, so that you have a little bit of cushion using the zoom of the lens. You never want to be on either extreme of the lens, other wise you may not be able to get the image to fit the screen properly.