Christie DS4K User Manual page 10

Section 2: Installation and Setup
Lens Type
0.73:1 fixed
1.45-1.8:1 zoom
1.8-2.5:1 zoom
2.5-4.5:1 zoom
4.5-7.3:1 zoom
2-6
Figure 2.1. Estimating Throw Distance
Vertical and horizontal position
The correct vertical and horizontal position of the projector in relation to the screen
depends on the lens type and the screen size. Ideally, the projector should be
positioned perpendicular to the screen. This way, the image will appear rectangular
instead of keystoned (trapezoidal).
The vertical position of the image can be offset – that is moved above or below the
optical axis (lens center) by adjusting the fully motorized lens mount with the keypad.
The amount of vertical offset available depends directly on the lens installed in the
projector and can be slightly limited if horizontal offset has been applied. Vertical
offset can also be expressed as the percent of half the image height OR the number of
pixels of shift from lens center. Refer to Figure 2.2 for some illustrated examples of
vertical offset.
Table 2.1 along with Figure 2.3 show the maximum vertical offset of a lens or
alternatively, how much of your projected image will appear above or below lens
center if the maximum vertical offset is applied using that lens.
Table 2.1. Lens Offsets
Vertical Offset
(% of Half Height)
% Pixels
37% +/-196
100% +/-525
100% +/-525
100% +/-525
100% +/-525
% Offset = # pixels of offset / half panel resolution x 100.
User's Manual
Maximum amount of
projected image above or
below lens center
% Pixels
69% +/-721
100% +/-1050
100% +/-1050
100% +/-1050
100% +/-1050
Horizontal Offset Maximum amount of
(% of Half Width) projected image to one side
of lens center
% Pixels %
22% +/-153 61%
50% +/-350 75%
50% +/-350 75%
50% +/-350 75%
50% +/-350 75%
Pixels
+/-853
+/-1050
+/-1050
+/-1050
+/-1050