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projector questions

Discussion in 'Projectors, Screens & Video Processors' started by themadhippy, May 5, 2002.

  1. themadhippy

    themadhippy
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    been asked to spec an lcd projector for work and need some help on a couple of points before i start annoying suppliers, who no doubt will all give conflicting advice.
    1) the distance from screen to projector is around 16 meters and image size is around 6.5 x 3. 5 meters,is this possible whilst still maintaing a high level of brigtness?
    2)do any projectors have a shutter/dowser(perferable remote controlled) like 35mm film projectors,or is their another option?(holding a piece of card infront of the lense isnt an option)

    noise levels arnt too important (anyone heard a 35mm in action will know what i meen) ease of use and easy maintenance along with a long lamp life are more important
    input wise it will be feed from dvd,video and pc ,
    have i missed anything?any sugestions of a suitable model gratefully accepted
    thanx all
    hippy
     
  2. Chris Frost

    Chris Frost
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    The screen shape suggests that you plan to show video/DVD. Is this right? Do you plan to display PC presentations too?

    There are two solutions for image brightness: Low cost = Dark room + modest powered projector (say 1500-2000 ANSI), or High cost = nutter light output + some room lights on. The budget route might come in for less that £4000, and with the other you could start talking at £10-15,000 and keep on going. What is your budget and what will the viewing conditions be like?

    The throw distance you want might require a semi-long throw lens. Look for lenses with a throw ratio of (16/6.5) 2.46.

    Lamp dowser - most single lens projectors can be switched off and this will stop it producing light instantly. You will need to let most cool down before the lamp can be struck again. If you want to switch instantly to the video projector from some other projector then this will be more difficult.

    You might find that the projector mute works OK (lamp lit, panels blocking light to produce grayish black) and that you can live with the small amount of light leakage on the screen.

    If you want no light from the projector then you will need some form of iris/shutter in front of the lens. There may be some commercial cinema projectors with this feature, but this isn't the place to enquire about those products as most home cinema enthusiasts don't have £1/4 million+ to spend on their hobby ;)

    Let us know budget, viewing conditions and what you plan to show.

    Regards
     
  3. themadhippy

    themadhippy
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    thanx chris ,ive been allowed £7500 net max(and i wont be aloud to buy any more toys this financial year:( )
    light levels ha well thats difficult,most of the time it will be almost total blackout but one use is the projection of images whilst some stage lighting is in use(but not directly at the "screen").
    as for source material it needs to be able to handle anything we throw at it,video dvd,data ect.
    the mute option may work, just depends how noticable the spill is
    pity theirs not a unit you can fit in the gate of a 35mm projector,would make life easier

    thanx again

    hippy
     
  4. Chris Frost

    Chris Frost
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    There are a few projectors with 16:9 panels, which would be a perfect choice for your screen shape, but none (AFAIK) have the sort of light power required to illuminate your screen within your budget. Those with enough power tend to use 4:3 LCD/DLP panels. This is OK for DVD and W/S based TV images, but PC and other 4:3 shaped images will be too tall for your 16:9 screen height. The result will be image spilling off the top and bottom of the screen.

    I have considered a couple of solutions. The most elegant is to find a projector with a zoom lens capable of filling the width of the screen for 16:9, and then zooming down to shrink 4:3 images so they fill the screen height. The downside to this solution is the time it takes to zoom and refocus, but on the upside this solution preserves the maximum resolution for PC presentations and the image becomes brighter as the size decreases. This is exactly what you want if presentations are made with the stage lights on.

    Philips has a projector that would work well here. The ProScreen PXG20 with optional long throw lens. This is 3000 ANSI lumens, XGA resolution with power zoom and focus. It would come in well under your budget. Other manufacturers may also be able to offer a solution.

    The alternative is an electronic aspect ratio controller. This would compress 4:3 images from PC and video to fit the height of a 16:9 screen. The benefit is that there is no zooming or refocusing, but the PC resolution suffers and the image gets no brighter when compressed.

    I have discounted using an anamorphic lens option. IMO the optical distortion would be too noticeable on your screen size.

    You should also budget for some sort of video scaler or deinterlacer. An iScan would be the budget solution, but a Quadscan or similar scaler would be better because it has multiple aspect ratios and RS232 control. A Quadscan wouldn’t resize PC images though, so don’t use it if you go for the alternative solution.

    To anyone about to suggest HTPC, please remember this is a commercial installation where ease of use (by some non-technical staff) and reliability are key. I know HTPC can be made to do wonderful things, but in this application it may introduce more problems than it solves:)

    Regards
     
  5. themadhippy

    themadhippy
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    many thanks indeed chris will look further into the ProScreen PXG20, re focusing for the varies images shouldnt cause any proplems,if its under budget all the better,(money saved=more toys)
    your right about the technical ability of some of our users/staff,give them more than 2 buttons to press and they get confused
    thanks again
    hippy
     

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