Screen Size; Screen Aspect Ratio - Christie Roadie HD+35K User Manual

NOTE:
Roadie HD+35K lenses are designed primarily for use with flat screens, but the projector's depth-of-field
range allows the lens to be focused on mildly curved screens as well. While focus remains sharp in the
corners, there may be significant pincushion distortion, primarily at the top of the screen.
Rear Screen Installations
There are two basic types of rear screens: diffused and optical. A diffused rear screen has a surface that spreads
the light striking it. Purely diffused screens have a gain of less than 1. The main advantage of the diffused
screen is its wide viewing angle, similar to that of a flat screen for front screen projection. Optical rear screens
take light from the projector and redirect it to increase the light intensity at the front of the screen. This reduces
it in other areas, and creates a viewing cone similar to that of a curved front screen installation.
To summarize, optical screens are better suited for brightly lit rooms where the audience is situated within the
viewing cone. Diffused screens may be better suited when a wide viewing angle is required, but there is low
ambient room lighting.

2.2.2 Screen Size

Screen size (image size) may be up to 150 feet across, depending on your lens and ambient light level. Choose
a screen size appropriate for your lens and application. Keep in mind that if the projector will be used to
display much text information, the image size must allow the audience to recognize all text clearly. The eye
usually sees a letter clearly if eye-to-text distance is less than 150 times the height of the letter. In other words,
small text that is simply located too far from the eye will be illegible no matter how sharply and clearly it is
displayed.
NOTE:
Screens with aspect ratios (proportion) of 4:3 are typically specified by diagonal size, but screens having
other aspect ratios, such as the 2048 x 1080 of the Roadie HD+35K, are usually specified by their
horizontal width. See

2.2.3 Screen Aspect Ratio

Aspect ratio describes the proportion of the display and is expressed as the ratio of width to height, such as
"5:4" or "16:9". Typical aspect ratios range from 1.25 to 2.35, the higher the value, the wider or "less square"
the image. Refer to
Roadie HD+35K User Manual
020-100340-02 Rev. 1 (01-2010)
Table 2.1 below :
Table 2.1 Matching Lens to Screen Size
Lens Type
0.8:1 fixed
1:1 fixed
1.25 - 1.45:1 zoom
1.45 - 1.8:1 zoom
1.8 - 2.4:1 zoom
2.2 - 3.0:1 zoom
3.0 4.3:1 zoom
4.3 - 6.0:1 zoom
5.5 -8.5:1 zoom
Table 2.2 below.
Section 2: Installation and Setup
Screen Width(< - >)
5 - 3 ft.
14 - 150 ft.
10 - 121 ft.
8 - 102 ft.
6 -83 ft.
5 - 66 ft.
3 - 49 ft.
2.5 - 35 ft.
2 - 27 ft.
2-7