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2.10 Adjusting the image position on the screen
On axis / off axis projection
The position of the projector with reference to the screen may also be different depending on the installation.
Basically the projector can be positioned in On-Axis or Off-Axis configuration. On-Axis configuration means
that the projector is positioned so as to have the centre of the lens coinciding with the centre of the screen.
Off-Axis projection is obtained by shifting the lens up, down, left or right.
Shift range
The lens can be shifted with respect to the DMD (P) which result in a shifted image on the screen (Off-Axis). A
100% shift means that the centre point of the projected image is shifted by half the screen size. In other words,
the centre point of the projected image falls together with the outline of the image in an On-Axis projection.
Due to mechanical and optical limitations it's recommended to keep the shift values within the field of view (F)
as illustrated below. Within these shift ranges the projector and lens perform excellently. Configuring the
projector outside these shift ranges will result in a slight decline of image quality.
G100 Vertical Shift range: 120%
G100 Horizontal Shift range: 50%
+120%
U
-50%
L
D
-120%
Image 2–16
D
DMD
F
Field of view
It is mechanically possible to shift outside the recommended field of view, but it will result in a
decline of image quality depending on the used lens and the zoom position of the used lens.
Furthermore, shifting too much in both directions will result in a blurred image corner.
See user guide for instructions on how to shift the lens holder (Installation menu > Lens Shift).
Recommendations concerning image reflections in dark images
Image artefacts are reflections of the off-state light on the first lens element back to the chip. In order to avoid
these type of image artefacts becoming visible in dark images, it is advised to shift the lens until the reflections
are outside of the visual area.
•
For lens R9802181, you do not have image artefacts when you shift up over +56% vertically.
•
For lens R9802182, you do not have image artefacts when you shift up over + 64% vertically, or if you shift
down below –22% vertically.
+50%
R
U
D
L
R
R5913458 /01
Prepare to install
+120%
-120%
-50%
+50%
G100
35
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