Epson PowerLite 51c Frequently Asked Questions

EPSON Answers
®
What is projector "throw distance" and how can I find out the throw distance
of an Epson projector?
To set up a projector properly requires an understanding of where to position the projector realtive
to the screen. Putting the projector too far away makes the image too large and faint. Placing the
projector too close to the screen makes the image toosmall. A projector's throw distance is a calcu-
lation that gives you the optimum distance for placing your projector.
Did You Know?
The basic rule is that light intensity decreases in inverse proportion to the square of the distance.
At a two-foot distance, light
will be 1⁄4 the intensity and
cover 4 times the area as the
same beam of light at a one-
foot distance.
So how do you determine your optimal throw distance? Whether you are presenting in a classroom, confer-
ence room, training room, or auditorium, you will need to know one of these two things in order to correctly
position the projector:
Screen Size — Once you know your room size and layout, you will need to know the size of the screen.
If the room you are presenting in has a built-in screen, measure the dimensions of the screen, including
the diagonal (corner to corner). This will determine where to postion your projector to adequately fill
the screen. If the room layout does not accommodate the throw distance you need, one alternative is to
use a projector with a replaceable lens that will provide either a longer or shorter thow distance than the
standard lens allows.
Throw distance — If you know the throw distance you require (based on the room layout) and what the
projector can handle, you can easily calculate the optimal screen size using the chart below. Basically,
the longer your throw distance, the larger your screen size will be.
EPSON PowerLite 51c/71c
Screen size:
Wide
Tele
Distance
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Knoware University at http://knoware.epson.com
1 foot
Distance
1
Intensity
Image Size 1X
36" 71" 105"
29" 58" 87"
4.2' 8.3' 12.5'
2 feet
1/4
4X
140" 175"
116" 144"
16.7' 20.8'
Summer 2002
3 feet
1/9
9X
210" 279" 313"
173" 231" 260"
25' 33.33' 37.5'
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348"
305"
41.7'