Screen size, Ambient light, Other considerations – Runco VX-2i User Manual

Page 25: Throw distance, Figure 3-2 . estimating throw distance, 2. estimating throw distance

Runco VX-2i Owner’s Operating Manual

Screen Size: Choose a screen size that is appropriate for your lens and application. The
size of the room and viewing distance are the defining factors; a rule of thumb is that the
primary viewing distance be 1.5 times the screen width.

To fill a screen with an image, the aspect ratio of the screen should be equal to the aspect
ratio of the image (expressed as the ratio of its width to its height). Standard video from a
VCR has a 4:3 or 1.33:1 aspect ratio. For example, to display a VCR output with a 4:3
aspect ratio onto a 10-foot (3.05-meter) high screen, the width of the screen must be at
least 13.3 feet (4 meters).

Ambient Light

In general, minimize or eliminate light sources directed at the screen. Contrast ratio in your
images will be noticeably reduced if light directly strikes the screen, such as when a shaft
of light from a window or floodlight falls on the image. Images may then appear washed
out and less vibrant.

Other Considerations

Other considerations and tips that can help improve your installation:

• Keep the ambient temperature constant and below 35°C (95°F). Keep the projector

away from heating and/or air conditioning vents. Changes in temperature may cause
drifts in the projector circuitry, which may affect performance.

• Keep the projector away from devices that radiate electromagnetic energy such as

motors and transformers. Common sources of these include slide projectors,
speakers, power amplifiers and elevators.

Throw Distance

Throw distance is the distance measured from the front of the projector to the screen.
This is an important calculation in any projector installation as it determines whether or not
you have enough room to install your projector with a desired screen size and if your
image will be the right size for your screen.

You can quickly estimate the throw distance by taking the width of the screen and
multiplying it by the lens throw ratio; see Figure 3-2. The result of this calculation tells you
roughly how far back the projector should be positioned from the screen in order to
project a focused image large enough to fill the screen.

Figure 3-2. Estimating Throw Distance

Estimating Throw Distance
Throw Distance (TD) = Screen Width (w) x Lens Throw Ratio

Scr

een w

idth (w)