NEC iS15-2K, Руководство пользователя

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page 2.16
2. Installation
iS15-2K
Cinema Projector: User Manual
Notes
Lens extension is measured
when the lens is focussed at
infinity, and fully extended. At
other focus settings, the
extension could be up to 10mm
less
Useful lens formulae and constants
The following lens calculations may be useful:
Throw ratio = Throw distance
Screen width
Throw ratio factor (TRF) = DMD width in pixels = 2048
image width in pixels image width in pixels
Therefore:
Screen width = Throw distance (from outer end of lens)
Throw ratio x TRF
Throw distance = Screen width x Throw ratio x TRF
The throw distance calculated above is to the outer end of the lens. For each lens,
the nominal distance between the front of the projector and the outer end of the lens
(lens extension) will be as listed below:
lens extension
1.45 - 1.8: 1 zoom lens 102-933 109mm (4.3in)
1.8 - 2.4: 1 zoom lens 102-934 97mm (3.8in)
2.2 - 3.0: 1 zoom lens 102-935 53mm (2.1in)
3.0 - 4.3: 1 zoom lens 102-936 98mm (3.9in)
lens extension,
measured from front
of corner post