how do current PJs compare with TV in Brightness and C/R

Discussion in 'Projectors, Screens & Video Processors' started by SanPedro, Oct 14, 2004.

  1. SanPedro

    SanPedro
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    As title, how well do the new crop of PJs (new Sony and Optoma) likely to compare to a normal CRT TV for daytime viewing?

    I still love my Panny AE100 but would like something you don't to black out the room so much to get a good pick.

    A quoted C/R of 6000:1 and brightness of 1200 lumens looks pretty good to me.

    Chris
     
  2. LV426

    LV426
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    Whatever the contrast ratio of the projector, it will never (*) work properly in high levels of light.

    A projector cannot project black. It can only project (at best) anything between nothing up to a given level of brightness.

    When a projector projects "nothing" the screen is still illuminated by whatever ambient light there is. The projector cannot make it darker than it wants to be.

    If the room is dark - then nothing = black (more or less) because there's no other light falling on the screen. If the room is light, then nothing = whatever colour the screen (as illuminated by the ambient light) is.

    And the screen by its nature needs to be light in colour - otherwise it wouldn't reflect the bright parts of the image.

    (*) Sony recently announced a new screen technology where the screen is paradoxically both dark in natural colour, yet able to reflect light. Not on the market yet AFAIK and I don't know how effective. If it is, then this may offer a solution.
     
  3. SanPedro

    SanPedro
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    Thanks

    I know it will never be fully watchable in a brightly lit room but so is a CRT TV. A TV will look equally washed out next to an open window.

    I'm just curious as to how these very latest products compare to a TV. I'd like to be able to watch TV and movies without having to blackout all the time.

    Chris
     
  4. LV426

    LV426
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    OK, try this. Take a look at any type of TV screen when it's off. They are all dark grey, or a sort of dark military green. And they illuminate by actually creating light right at the point where you watch. Anything unilluminated is whatever colour you see when its off. Fairly dark, in pretty much every case.

    Then, take an (imaginary if necessary) look at the colour of a projector screen when there's no projector. It's white or very nearly. A projector screen works by reflecting (as opposed to creating) light so it has to be light in colour (Sony's new ideas aside).

    The is the key difference, and no amount of projector performance is going to solve it.

    Or, to put it another way - consider the huge amount of light output from a cinema arc lamp, and the contrast obtainable from film. When was the last time you went to a cinema that had anything more than a minimal (for safety) amount of ambient light?
     
  5. BadAss

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    Put another way. Your projector never shoots out white or black. White is just pure light and your screen doesnt know if the light hitting it is from your projector/ceiling lights/torches etc. Blacks are made from lack of light where LCD projectors are not perfect, leeking light through the pannel.

    A projector will reflect what light hits it, but not only that, the iris in your eye will close with the more light it receives blocking out even more light. So on a sunny day your eyes have allready blown your PJ brighness away before youve turned it on. Your iris needs to be fully open and your screen reflecting only light from your projector before youll see the PJ maximum output levels.
     

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