Christie roadie 25k User Manual page 17

INSTALLATION AND SETUP
Figure 2.11. Estimating Throw Distance: Example
NOTE: If your projector is slightly tilted in relation to the screen, typical for large
venues and/or elevated installations, throw distance still represents the smallest
measurement between the screen and projector.
As shown in Figure 2.11, throw distance is approximately equal to the horizontal
width of the screen multiplied by the type of lens you are using. For example, if you
are using a 1:1 lens, proper throw distance will be approximately the same as screen
width. Once you know your screen width and lens you can estimate throw distance
needed. Or, if you know throw distance, you can determine what images sizes are
possible with a given zoom lens.
IMPORTANT:
For proper placement in any installation, use the throw distance
formula provided for your lens (Appendix D). In addition, please keep in mind that
due to lens manufacturing tolerances for lens focal length, actual throw distance
can vary ±5% or more between lenses described as having the same throw ratio.
For complete throw distance information, consult Appendix D.
Vertical & Horizontal
'
Refer to the offsets shown here for help in determining how high or low to install the
Position
projector in relation to the center of the screen, and/or how far off to one side.
VERTICAL POSITION
describes the elevation of the projector in relation to the screen.
For many typical rental/staging installations, the projector will be above screen
center. An ideal vertical position helps ensure that images will be accurately
rectangular in shape rather than distorted into a keystoned shape with non-parallel
sides, and that image focus and brightness both remain optimized.
NOTE: Proper vertical position is recommended, although vertically keystoned
images (i.e., those with sloping sides) can be corrected in software. See Section 3.
Vertical position of the image can be manually offset—that is, placed higher or lower
in relation to lens center—using the vertical offset knob on the lens mount. Starting
with no offset, the 2048 x 1080 image from this projector can be moved by a
maximum distance of 540 pixels, resulting in all of the image displayed above or
below lens center (Figure 2.12).
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Roadie 25K User's Manual