NEC iS15-2K User Manual

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NEC iS15-2K User Manual Manual pdf 31 page image

page 2.15iS15-2K Cinema Projector: User Manual 2. InstallationNotesThe Throw ratio for a particularlens is fixed, but assumes thatthe image fills the width of theDMD.For images that do not fill thewidth of the DMD, the Throwratio is effectively increased. Tocorrect for this in thesecalculations, a Throw RatioFactor (TRF) is used.The lenses available and theirpart numbers are listed below:1.45 - 1.8: 1 zoom lens 102-9331.8 - 2.4: 1 zoom lens 102-934(note: these two lenses overlap)2.2 - 3.0: 1 zoom lens 102-9353.0 - 4.3: 1 zoom lens 102-936Method two: Choosing a lens by calculationFor any screen size not covered by the lens charts, or if you need to be moreprecise, then use the calculations below.• Identify actual width of the image in pixels.• Calculate the Throw Ratio Factor: TRF = DMD width (2048)Image width in pixels• Identify the screen width required.• Identify the throw distance required.Throw distance calculations are based on the distance from the outer end of thelens, which will vary from lens to lens. Once a lens has been chosen, the figurescan be checked using the more accurate figures given on the next page.• Calculate the throw ratio required. Throw ratio = Throw distanceScreen width x TRF• Choose a lens with the required throw ratio from the list to the right.example• A 1.66:1 full height image, 1793 x 1080 pixels, screen width 11m, throw distance26m from the outer end of the lens.• Throw Ratio Factor (TRF) = 2048 = 1.1421793• Throw ratio required = 26 = 2.0711 x 1.142• Choose the 1.8 - 2.4: 1 zoom lens