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PJTX100: How does the lens shift affect the achievable screen size/projection dist.?

Discussion in 'Projectors, Screens & Video Processors' started by BigToes, Aug 6, 2004.

  1. BigToes

    BigToes
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    I'm considering buying the Hitachi PJTX100; seems to be a good buy :thumbsup: . However, I haven't been able to find any information concerning how the lens shift affects the achievable projection distances and screen sizes. Please help me out....

    At the moment I am considering the following distances: projection distance 5.0m, vertical offset 1m (to center of screen), horizontal offset 1.2m (to center of screen). My target screen size is 110" (or less). (Other placements of the projector is tricky in this room.... e.g., ceiling mounting is not an option. I could go with zero horizontal offset, but still need 1m of vertical offset.)

    Does anyone possibly know the formula for computing the screen size for the PJTX100 with following inputs: projection distance, vertical offset, and horizontal offset? Or provide a table with some example values? (I would prefer a formula though.)
     
  2. dither

    dither
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    I don't have a formula, but I looked at the tx100 in some detail recently, so here goes:

    A 110" image is about 2.4m wide right? So 1.2m horizontal offset is 50% - which is more than the tx100 can do, 25% is the max. The manual is online somewhere (can't remember where I got it) and it shows this quite clearly. The vertical shift you want though is within the range (just), and the image size is within the zoom size (just), so I would guess that you would be able to get this image, or one a little bit bigger.

    If the 110" figure is a hard limit though I'd say you need to try it - even the manual tables (with no lens shift) say the figures are only +/- 10%.
     

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