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To Gain or not To Gain That is the ?..

Discussion in 'Projectors, Screens & Video Processors' started by Hal, Oct 1, 2004.

  1. Hal

    Hal
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    I have a panny 700 on odere dose not get here till the end of the month :(

    wile lest it gives me time to get my cinema room ready.

    I am abount to get a nice big screen, should I go for a high gain screen or just stick with a simple matt ?

    Can any one give me a few pointers on the pros and cons of both and some idears

    T.I.A
     
  2. Hal

    Hal
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    anyone ?....
     
  3. KraGorn

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    What size are we talking here?

    I've not researched the 700, but given its' nominal 1000 lumen output, then IMHO you'd not want anything exceeding a 1.2 gain, albeit the actual output will be a LOT less than this figure.

    PS, 2 hours is a little short to expect too many responses, especially during a weekday afternoon. :)
     
  4. Hal

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    :blush: sorry I for get that this maby the center of my world its not every ones..

    As for size it will be abount 5 - 6 ft mark not that big a room but its going to be all cinema :D
     
  5. nelius

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    I've ordered the AE700 myself and went for a 1.0 Gain screen.
     
  6. Hal

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    I am blocking the window, so that I can have the screen there. so there will be no out side light at tall. I will be watching films in the dark but will want some light on when I play on the xbox or watch the formla 1. If my understanding Of hi gain screens is right a high gain will help me have some aberent light in the room and still get a good pic....

    This will be my frist pj so I am looking for info from some off the old hands
     
  7. theritz

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    Hal,

    I'm assuming that english isn't your native language - your posts are a little hard to understand. If you're going for a 5 - 6ft wide screen then I would say that a normal matt 1.0 gain screen will do - the AE700 should be plenty bright. As far as ambient light is concerned, any light falling on the screen will wash out the image - it just depends on how much light you anticipate.

    S.
     
  8. KraGorn

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    In general, with this sort or projector any ambient light is BAD, as TheRitz point out.

    A high gain screen can help to a limited extent, the main reason for choosing a high gain AFAIK is to help larger screens deal with less-bright projectors .. given that the 700 is one of the brighter projectors in this part of the market then a unity gain is probably fine at the 5-6' size.
     
  9. Hal

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    thx for the info m8.

    I suffer from (there is a latin word for it wich I can not spell :blush: but It means word blindnes)

    so you guys will have to bare with me abit.......
     
  10. Gary Lightfoot

    Gary Lightfoot
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    There is a way to calculate how much light will be reflected from a screen - you divide the lumens of the projector by the square foot area of the screen.

    So, if you have 1000 lumens, first deduct approximately 40% due to lamp dimming and inflated manufacturers figures, so lets say you have 600 lumens.

    We will say that you will be using a 6ft wide 16:9 screen, so the dimensions will be 6ft x 3.375ft which gives an area of 20.25.

    Divide 600 by 20.25 and you get 29 foot lamberts. If you have something other than a unity gain screen, multiply the result by the gain figure. The number of foot lamberts required for a cinema is 12 to 16 - 12ft lamberts when there is film in the gate, and 16 without. It was derived to reuce film flicker but works well in the home too.

    So: lumens / screen area X gain = ft lamberts.

    Of course, this is for a fully light controlled room, which is what you will have, so as has already been said, for your choice of screen, a matt white will be fine.

    If you introduce some ambient light, you could even try a grey screen - a 0.8 gain grey screen will help with black level and reduce the effects of ambient light. Multiply 29 x 0.8 and you get 23 ft lamberts, which is still fine for your situation.

    I'd advise trying to get a grey screen demo if possible, as not everybody likes them.

    HTH

    Gary.
     
  11. Hal

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    cheers m8 will try and get that demo soon
     
  12. KraGorn

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    I started off with a 92" grey screen and a Panny AE300 .. it worked very well in increasing 'blackness' but after a time I became unhappy with the loss of light it caused .. however, a 700 on a 6' screen could probably cope well with the loss of light and could be very effective I would think.
     
  13. Hal

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    I am going to look at this from a diffrent angle. What are the down sides to a high gain screen. I no it can give you a sweet spot but as my room is not there wide that should not be a proplem....
     
  14. homeagain

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    I have a 74" screen for my AE500. Originally it was a homemade MDF job with Icestorm 4 top coat. This is a darker grey than most use but I wanted acceptable blacks ( my previous projector was a NEC 9PG+ CRT ) so I also added a Hoya ND2 filter to the Panny. In low lamp mode I had good blacks but a pretty dim picture. I finally managed to get some Dalite HCCV screen material sent out and built a new screen, also 74" diagonal. I would estimate the old screen had a negative gain of about .7 -.8, whereas the Dalite is a positive gain of 1.1. This made a dramatic difference to contrast, brightness and overall punch to the image. Interestingly both Icestorm 4 and the HCCV material are almost an identical shade of grey and therefore black levels have remained the same. I continue to run in low lamp mode.
    Just my tuppence worth, hope it helps.
    Cheers, Rob. :thumbsup:
     
  15. Gary Lightfoot

    Gary Lightfoot
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    Not wanting to be pedantic. :)

    Screens don't have negative gain - it's still positive, but less than unity (one), so 0.8 is still postive because it's above zero.

    Just thought some may find that interesting, but possibly geeky. :D

    Gary.
     
  16. homeagain

    homeagain
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    I stand corrected. LOL. :rolleyes:
     

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