Runco Reflection VX-3C, Owner'S Operating Manual

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D-1
Always consult this Appendix when planning a projector installation. See also 2.3, Projector Position and
Mounting.
Calculating Throw Distance
Correct throw distance depends on the screen size and lens present-the larger the image needed,
the greater the distance you must allow between the lens and screen. Once you know the screen
size and lens type present, you can calculate the precise throw distance you require by using the
appropriate formula as found in this appendix.
Throw distance is the distance between the pro-
jector front feet and the screen. This measure-
ment is not necessarily parallel to the floor-i.e.,
the projector and screen may be inclined.
NOTE: If your projector is tilted up or down in
relation to the screen, as is sometimes the case
for large venues or elevated installations, throw
distance still represents the smallest measure-
ment between the screen and front feet centers.
Pre-calculated throw distances for the complete
range of lens types and screen sizes appear in the charts and graphs on the following pages. Refer
to these examples to quickly determine the proper throw distance (±5%) for your installation and
lens.
NOTE: Variable operating ranges for zoom lenses appear in graphs only.
Throw Distance
Appendix D
Table E-1. Throw Distance Formulas
Lens Throw Ratio Throw Distance Formula (ft.) ±5%
Diagonal Screen Size
ù
(ft.)
0.8:1
(Optional)
.79 x screen width ( ft.) + .81 5-25
1.2:1
(Optional)
1.24 x screen width ( ft.) + .82 5-30
1.5-2.2:1 zoom
Min: 1.52 x screen width ( ft.) + .57
Max: 2.26 x screen width ( ft.) + .44
5-40
2.2-4:1 zoom
Min: 2.23 x screen width ( ft.) + .61
Max: 4.09 x screen width ( ft.) + .36
5-40
4-7:1 zoom
Min: 4.03 x screen width ( ft.) + .57
Max: 7.13 x screen width ( ft.) + .27
8-40
NOTE: Make sure to use HORIZONTAL screen size in all formulas.