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Real world differences between H77 and H78DC?

Discussion in 'Projectors, Screens & Video Processors' started by Lobo, Jul 21, 2005.

  1. Lobo

    Lobo
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    Now that I hear Optoma are providing the H78DC over here I would like to know what the real world differences are to the H77 that would be noticable. I viewed an H77 a while back but was hesitant to purchase it due to the black levels (although I admit I didnt have it setup anywhere near optimally).

    Anyone seen either of these to be able to compare?

    Also, how different will the H78DC be from the H79?
     
  2. Gary Lightfoot

    Gary Lightfoot
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    The H79 has a contrast ratio of 2900:1 when calibrated at D65 (will be higher uncalibrated) compared to the H77 which is around 2300:1 out of the box - the UK H78 is around 2400:1 OOTB and both will be slightly less when calibrated to D65. The UK H78 is capable of 2700:1 CR with a lens filter, and this will also improve the black level as well, though you will need an ISFer like Gordon to do this for you.

    Black level is dependant on the screen size and gain (in a light controlled room), so a small screen will give a brighter image than a larger screen. If you want better black levels I would aim for cinema levels of reflectance and calculate screen size and gain requirements using around 450 lumens for low lamp and 575/600 lumens for high lamp for the H78DC3. Those are guestimates based on an expectation of improved lumen output over the existing H78 until we can actually measure it and know for sure.

    I am guessing The DC3 H78 will have somewhat more CR (2700:1 to 2800:1 @D65 maybe) and will be possibly be brighter too. Either way, I would think there would be an improvement in performance compared to the existing UK H77/8 models.

    The H79 has been reviewed in detail by Greg Rogers of Widescreen review so we have some 'definitive' data on it for reference. Lets hope the H78DC3 gets similar treatment so we can find out just how well it compares.

    Gary.
     
  3. Joe Fernand

    Joe Fernand
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    Hello all

    Lobo - the key difference is that the H77 is a discontinued HD2+ DLP Projector and the H78DC3 doesn't exist (in the UK anyway).

    Until ThemeScene (Optoma) UK make an announcement about releasing a DC3 equipped projector the H78 (HD2+) is the current 'flagship' model in the UK.

    ThemeScene in the UK held off releasing a UK spec H79 as the price point would have been around £4.5K and I guess they see the main market as being around £3.5K.

    I'm amazed how many folk say they go to 'see' a projector and then view it in less than ideal circumstances.

    As Gary points out once you have the ideal surroundings you also want to ensure the video chain has been carefully calibrated to ensure you are getting 100% performance out of the system your viewing.

    I'm sure if ThemeScene UK do decide to make some changes to the current line up (H30A, H57 and H78) there will be plenty of info on AVForums about a minute after dealers are updated :)

    Best regards

    Joe
     

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