Projector Position And Mounting; Throw Distance - Christie Roadie HD+35K User Manual

Section 2: Installation and Setup
2.3

Projector Position and Mounting

Installation type, the available screen, and ambient lighting all affect where the projector should be positioned.
In addition, both throw distance (the distance between the projector and screen) and vertical position (the
height of the projector in relation to the screen) must be determined for every new installation. Both depend on
the screen size and lens type you are using. Make sure that the room can accommodate the required location of
the projector for the chosen screen size.

2.3.1 Throw Distance

Throw distance is the distance between the projector and the screen (see
placing the projector at an accurate throw distance is necessary in order for the image size to closely match
your screen. The farther the projector is from the screen, the larger the image. With zoom lenses, you'll want to
know the approximate minimum and maximum image sizes possible from a given throw distance so that the
most appropriate lens is installed at the site (throw distance/screen width = throw ratio).
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
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 type of 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.
2-12
x
Screen Lens Type
Figure 2-13 Estimating Throw Distance: Example
2-13, the throw distance is approximately equal to the horizontal width of the screen
= Approx. Throw Distance
In this example, a throw distance of
18.75 feet will project an image
approx. 13-15 ft wide, depending
on the zoom setting.
1.25-1.45 zoom lens
Figure 2-13). For any installation,
Roadie HD+35K User Manual
020-100340-02 Rev. 1 (01-2010)