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Aspect ratio query

Discussion in 'Projectors, Screens & Video Processors' started by gorwig, Aug 31, 2005.

  1. gorwig

    gorwig
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    Hi Chaps.

    I`ve built my own screen (ripple free - Hooray!!!) to be exactly 16:9 (160cm x 90cm - simple!). When I view 2.35:1 images the picture fits the screen horizontally with the usuall black borders top and bottom. The problem occurs when I view 1.78:1 (16:9) material. Again the image is fine horizontally but there is overlap top and bottom with the image extending out of the white viewing area, over the black border frame and onto the wall.
    My Denon 1910 is set to 16:9 and so is my Infocus 5700 and the picture is definately in the correct aspect (i.e not streched or squashed).
    Does anyone know if commercial fixed screens are exactly 16:9 or are they produced with a bit of latitude vertically?
    I don`t know if I have an electronic aspect missmatch or wether I`ve been naive in building an exactly 16:9 screen.
     
  2. fortean

    fortean
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    You may have set up your projector/screen using a 1.85/1 image. This means that when you play a 1.78/1 image you have the overshoot area. For a 160cm wide image at 1.85/1 you would need 86.5cm height whilst a 90cm height would give you a 166.5cm width.
     
  3. Voiceedit

    Voiceedit
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    Do you mask the black areas when projecting a 2.35:1 ratio image? If so you could perhaps modify your mask positions to allow a small amount of top and bottom masking for 1.85:1 while removing the masking completely for 1.77:1. You may also need to apply some lateral masking on 1.85:1 depending on the DVD. I assume yours is a LCD or DLP projector with a zoom lens. Had you made your screen at 2.35:1 to start with, masking for other ratios would have been easier.

    If you have no masking then the zoom should be used to make the top edges of the picture fit the screen in 1.77:1 mode - you'll then have small vertical blank left and right edges. It's a pity we have to contend with all these ratios. Have you tried any DVDs of older films originally made in 70mm which have been mastered onto DVDs in their original 2.2:1 ratio, or Ben-Hur which is in approximately 2.75:1? Having masking able to cope with all these makes life interesting, to say the least!
     

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