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True high definition with the new D5 panels

Discussion in 'Projectors, Screens & Video Processors' started by nelius, Oct 20, 2004.

  1. nelius

    nelius
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  2. Tempest

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    1920 x 1080

    Ohhhh, yes... Can I have it now please :)
     
  3. zoolap

    zoolap
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    Wonder what could be done with this combined with Sony/Panasonic auto?

    What do you guys think the effect will be on screen door with this new chip?
     
  4. SamirP

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    750:1 (720p) & 600:1 (1080p) contrast doesn't sound so good. I thought the new D5 panel's were meant to take LCD to DLP levels of contrast.
     
  5. explicitlyrics

    explicitlyrics
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    yes but as i understand it a fair bit of the contrast comes from that 'openy closey flappy thingy'!!!!!

    Lol
     
  6. Tempest

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    I may be totally wrong here, but I'm wondering if we are (in some way) cheating as little with these advertized contrast levels.

    The (technical description - openy closey flappy thingy) Is this REALLY giving us what we are expecting or is it fudging the issue a bit.

    meaning, a CRT or DLP giving REAL contrast ratio's. Is this new LCD idea really comparable, or are we compairing apples to oranges here ?

    Are we saying, bright white image, flappy things fully open, vs black image with flappy things totally closed.

    Meaning when flappy things are closed, other parts of the image will not be as bright.

    I'm saying are we compairing what you would see on screen at any one time. eg: a white white next to a black black.

    or are we saying a white scene compaired to a dark scene moment later.

    But not at the same time.

    If anyone knows the hell what I'm talking about !!!
     
  7. explicitlyrics

    explicitlyrics
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    I understand you but as I see it the contrast must be taken over a short time frame, given with dlp you will only have one colour on the screen at once so a selection of frames must build the contrast.

    There could also be an effect of having 3 lcd panels, you may add up the contrasts or similar. Im not really sure but if all pixels are on (closed) then it is darker than just 2 being closed so there must be an effect somewhere...
     
  8. Tempest

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    I guess I'm a bit suspicious....

    If the flappy things close down, block the light output the screen goes darker, darker blacks but then everything else is darker also, but as the surrounding is black, the hopefully you won't notice.
    Then we change to a bright scene, the flappy things open fully, ohh isn't it bright.

    But hang on a moment, we can't have bright whites and dark blacks at the same time. only in different scenes.

    I'd have thought this was cheating really, and not how CRT and DLP achieve their contrast levels.

    I guess I'm thinkng that flappy bits closed means EVERYTHING will be darker, not just the blacks.

    But perhaps you don't notice this cheating, in which case I should shut up :)
     
  9. theritz

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    Tempest,

    It's easier (and quicker) to type "iris" than to type "openy closey flappy thingy" :D

    The CR is being measured as the light coming out of the projector - what happens to it befor it hits the light metre really doesn't matter a hoot - it's the result that counts, and in the case of the HS50/51, counts big time...

    Modulating the light in the light-engine of an LCD projector is not "cheating" - it's just a smart application of an existing technology.......

    Sean.
     
  10. Tempest

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    Iris... openy closey flappy thingy.... hmmmm, you may have a point there!!

    Well, I'm not sure I agree..... (Takes a stand!)

    Surley, it's how it looks on the screen, the difference between the brightest and the darkest parts of an image is what we are (in reality) thinking of.

    being able to open up all the ports and let the light blast thru, making everything bright, and closing down the hatches so everything looks dark.

    Then saying, wow look at the contrast between those different levels.

    Ummm, yeah, but it's not doing it at the same time is it ? Which surley is what people are expecting.

    hey, I can turn my projector on with a white screen then off, and I get an incredible contrast ratio !!! (silly, but an extreme point)

    I'm just saying, this:

    Say we have a white surround and a planet earth.
    It's all bright.

    Now say whe have a black surround and the same earth.
    The iris closes down so the light output goes down to EVERYTHING.
    Making thr black look blacker, but then so does the earth, which is not as bright as it was when it had a white surround.

    is this how it works ?

    If you don't notice it, then great, but it's still cheating.
     
  11. MikeK

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    Most of the figures bandied about are cheats of one form or another anyway, especially in relation to home cinema use of a projector!!

    View them and compare them etc - but really all that matters in the end is the result on the screen and how much you have to pay for it!!!! :) :)
     
  12. Tempest

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    Yeah, I fully agree.....

    It's just that these contrast figures that are being bandied about by the LCD projector makers are being looked at along side say CRT projectors.

    I'm not sure you can compare these figures side by side across the two technologies.

    A CRT can do a white area and also have a black area on screen all at the same time, and achieve big contrast figures.

    I'm just wondering if this magic adjustable iris on the new LCD machines actually offers the same thing. light and dark at the same time.

    If not, then you can't really compare the new LCD's against anything other than the old LCD's.
     
  13. explicitlyrics

    explicitlyrics
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    yes but while this seems to be the way it works, surely it is the overall image quality that dictates how much contrast there is.

    Another point is that as far as i can remember there arent many films with really dark and really bright on at the same time.... May be wrong but anyway if the image looks good i dont mind how it is achieved.....
     
  14. MikeK

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    A CRT can do a white area and also have a black area on screen all at the same time, and achieve big contrast figures.

    This may be true, but it's still all a bit false IMO in that few people actually watch contrast patterns.
    Many of the tests and specs etc are quoted in best case scenarios for that projector - the makers always want to make the spec sheet suggest that a product is better than it really is.

    An extreme example - someone could make a high res PJ which could show nothing but full on white and full off black (no colour and no greyscale etc). You probably couldn't tell from just looking at the spec sheet (they'd conveniently omit what they didn't want you to know :) ) - the contrast ratio and ANSI lumens rating etc would all be there and look good on paper - however, it would make a pretty lousy video projector, no matter how good those figures looked on the sheet!

    Many specs are actually pretty meaningless IMO, if you don't know how the figure was arrived at, or what it's actually telling you - this car does 80mpg, this amp is 7x120W, this hard drive is 150MB/s, this CPU is 3GHz, this subwoofer does 20Hz .....and so on. We are bombarded all the time with specs which often bear little relation to the real world performance of a product. And when it comes to comparing specs from different manufacturers...well it's often equally meaningless if the same measurement conditions weren't used (and you don't often get to know that).

    Not saying a spec sheet is totally worthless, but personally I often don't pay the figures that much attention really. The sheet can often be informative by what it doesn't tell you as well - often they leave you with more questions than answers!
     
  15. Tempest

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    I look forwards to seeing all these active iris things in action.

    I guess I'm thinking about the following:

    Bright LCD screen, running a nice looking image, means grey blacks, esp the bars above and below the screen which will be grey due to fully open iris.

    Then we go inside the alien! building, down the really dark corridoors, and the iris closes, the (what were) grey bars now darken due to less light coming from the projector but also the overall image dulls down too.

    If you blanked off an area of black during a movie (say the black bars) and just watched that. would they be going up and down in greyness all the time ?

    I'm thinking here of say Alien 1
    There's a LOT of very dark scenes, following the alien down corridoors. whilst everything is dark, and the pinpoints of light (like the flame from the flamethrower) going to lack a bit of ooomph as the overall image brightness has been reduced due to the overall brightness being reduced?

    I think I've done this worry to death now :)
    But If this is how it works (which seems to be) I don't think we can really be saying WOW look at how the contrast is better then DLP and CRT as it's being achieved in a totally different way.

    Of course, I'd love someone who works in a shop and can see these different projectors for real to actually give their opinion.
     
  16. Barcoing Mad

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    It's important to distinguish on/off contrast ratio and ANSI contrast. The latter is measured with a white/black square pattern as image and shows up the effects of light scatter in the optics spilling into black regions.

    For scenes which contain bright areas, the ANSI contrast is a better measure. LCD and DLPs will out perform a (non liquid coupled) CRT PJ with ease. However, the eye/brain is very good at seeing grey and thinking black, when the surroundings are bright. A contrast range of a few hundred to one is excellent in these circumstances.

    For dark scenes, the CRT wins out with its black level- and traditionally LCD has fallen flat.

    A dynamic iris should work well for dim scenes- from the diagrams I've seen, the Sony iris looks professional. The Panasonic less impressive.

    The iris will have more difficulty with something like a starlit sky. There is sufficient peak white for the iris to need to open,with a concomitant rise in black level (greying out), but there is insifficient white to trick the eye/brain into perceiving a black background. There are two options- open the iris and live with it, or crush the whites. With luck Sony and Panasonic are bright enough to have hit a compromise that fools the viewer most of the time.
     
  17. Tempest

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    Thanks for that excellent posting.
    Yes, the stary sky is an excellent example.

    Ideally you'd have a nice black (or near black) sky with bright white points of light, which as you say can't be done with even the new LCD's and their iris tricks as you can't do white spots and black blacks at the same time.

    Can a DLP do this ? They don't use any tricks to achieve their contast level do they ?
     

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