ANSI lumens

Discussion in 'Home Theater Projects' started by john>III, Sep 14, 2004.

  1. john>III

    john>III Auditioning

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    Is there any way to tell by what method a manufacturer is measuring ANSI lumens....off the screen...off the lens...off the bulb? Comparing different brands is laughable. BenQ is specing theirs all at atleast 1,500 and most over 2,000, whereas Yamaha is specing their LCD at 1,000. Anyone know of a chart as to whom is measuring what?
     
  2. Charlie C

    Charlie C Stunt Coordinator

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    did you gooogle it? seems to me that ANSI lumens have been standardized a while back. I wouldnt say its gone to how amp wattage is rated. My frist proj was 1000 lumens and I thought it was a tad faded, I wanted something brighter. so when I get my next proj, Ill be looking at 1500 and up. I dont get your confusion. I think if each manufacturer wanted the 'better' spec, they would all be measuring off the bulb.

    I think ANSI is quite credible

    http://www.ansi.org/
     
  3. Dennis XYZ

    Dennis XYZ Stunt Coordinator

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    The measurement method may be standardized but they don't require the projector to be calibrated for a good picture before they measure it. Most of the manufacturers just crank everything to the max and take a measurement. After calibration, most projectors are only 1/2 to 2/3 as bright as their advertised number.
     
  4. Chris Brock

    Chris Brock Second Unit

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    i can honestly say i also see what you are saying. take these two projectors for instance.............

    http://www.projectorpeople.com/homet...nic+PT%2DL300U

    800 lumens
    800:1 contrast

    http://www.projectorpeople.com/homet...me=BenQ+PB7220

    2500 lumens
    2000:1 contrast ratio


    now the price is basically the same for both yet the differences in specs are stagering. how is it that 1 projector can have over 3 times the brightness capability and well over double the contrast ratio and yet be the same price? or are ones numbers simply blown out of proportion?
     
  5. Shawn Keeler

    Shawn Keeler Stunt Coordinator

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    This is probably one of the most frustrating things when shopping for a projector. There are no real guidelines and it seems manufactures always inflate their readings to make there product more appealing. In my situation, I made sure I demode the model(s), to actually see the picture, before I considered purchasing it. Reason being, specs to me are irrelevant. I need to see what the picture looks like, and let that be the judge. Obviously, if you have totally light control in your theater, what difference do the lumens make? Again, thats just me....but I would definitely take into consideration the room itself.
     
  6. Shawn Keeler

    Shawn Keeler Stunt Coordinator

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    This is probably one of the most frustrating things when shopping for a projector. There are no real guidelines and it seems manufactures always inflate their readings to make there product more appealing. In my situation, I made sure I demode the model, to actually see the picture, before I considered purchasing it. Reason being, specs to me are irrelevant. I need to see what the picture looks like, and let that be the judge. Obviously, if you have totally light control in your theater, what difference do the lumens make? Again, thats just me....but I would definitely take into consideration the room itself.
     
  7. Leo Kerr

    Leo Kerr Screenwriter

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    1200 Lumens: means... nothing!

    1200 ANSI Lumens: means... something!

    I believe the way they measure lumens is to put a integrating plate in front of the lens and measure how much light comes out in a full-white situation. ANSI, of course, will have detailed explanation of just how to do it, and is generally 10-30% lower than the non-ANSI number.

    Contrast is a little different, and does not take the screen into account.

    For regular Contrast, project a full white field onto your screen. Find the brightest spot, and record it. Turn the projector off, turn off any lights, and black out any windows, and find the darkest spot on the screen, and record that. Find the ratio. (To go back to an earlier point, this is done with an incident light meter, on the screen, pointed at the projector.)

    For ANSI contrast, project a 4x4 checkerboard pattern of black and white. Measure the center of each box, averaging the 8 black measurements against the average of the eight white measurements.

    A 'standard' contrast of 1000:1 will generally translate to an ANSI contrast of 200:1 - 350:1.

    Leo KErr
     
  8. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    In the PJ biz, we speak of ANSI Lumens and Marketing Lumens. Marketing Lumens are all over the map and are what's advertised.
     
  9. Chris Brock

    Chris Brock Second Unit

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    ok that definitly helps me a bunch. That makes total sense. Thanks alot!!
     

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