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Discussion Starter · #1 ·
I posted this on the Screens forum but didn't get any takers. maybe I'll have better luck here.


As a potential LT150 owner and a projector newbie, I am confused about:


1. How different aspect ratios affect the size (diagonal, width, and height) of the projected image. Is any dimension fixed as the aspect ration changes?


2. The LT150 User Manual includes a Throw Distance chart that provides values for a 4:3 diagonal. How can I convert the values for a 16:9 diagonal?


3. I will be using the projector primarily for watching DVDs. Should I get a 16:9 or 4:3 screen if I am not that concerned about the 4:3 image size? If I get a 16:9, will I have to move the projector (closer to the screen) to get a 4:3 image on the screen without any screen overscan?


I will only be connecting an RP91 DVD player (component connection) and will not be adding a scaler or lens (eg. panamorph).


Thanks.
 

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1. If the Resolution is set for Auto and the source is not controlling the aspect ratio, the width of the image is fixed. The Normal aspect ratio fills the entire 4:3 DMD panel. The Cinema aspect ratio uses a 16:9 portion of the 4:3 DMD panel. See link below for displaying 4:3 on a 16:9 screen.


2. 16:9 width = 4:3 width.

16:9 height = 9/16 of 4:3 height.

16:9 diagonal = square root (height squared + width squared).


3. I prefer a 16:9 screen. http://www.avsforum.com/ubb/Forum10/HTML/007300.html
 

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Discussion Starter · #3 ·
Signal,


Thanks for the info. Using it and the NEC formulas, I calculated that for my room size (seating distance from the screen and the projector's throw distance) that the maximum 4:3 screen that I can use is 72" diagonal (approx. 58"x43"). And that should give me a 16:9 image size of 66" diagonal (approx. 58"x32"). Does this sound correct?


But wait, how does the LT150's Cinema/Native Mode affect the calculations? Native Mode 1 is going to shrink the 4:3 image to fit within the 19:6 screen size correct? So the 4:3 image will be approx. 32" high, 43" wide and 54" diagonal (rather than 43x58, 72).
 

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I think your calculations are correct except Native Resolution and Normal Aspect Ratio (4:3) may be slightly smaller; perhaps 640x480 centered within the 1024x576 16:9 screen.
 
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