Positioning the projector, Calculating image size and projection distance – Epson 7800P User Manual

Page 4

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EPSON PowerLite 7800p Projector

5/03

EPSON PowerLite 7800p Projector

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3

Positioning the Projector

Follow these guideline when deciding where to place the
projector:

❏ Place the projector on a sturdy, level surface.
❏ Make sure there is plenty of space for ventilation around

and under the projector. Do not set it on top of anything
that could block the vents under the projector.

❏ Make sure the projector is within 10 feet of a grounded

electrical outlet or extension cord.

Image size increases with distance, but varies depending on
how you’ve adjusted the optical zoom and other settings.

It’s best to place the projector directly in front of the center of
the screen, facing the screen squarely. If it isn’t placed this
way, the image will be “keystone” shaped, instead of
rectangular.

If you place the projector below screen level, you’ll have to tilt
it up by extending the front adjustable foot. This also causes
the image to lose its rectangular shape. To correct distortion,
see “Adjusting the Image Shape” on page 8.

Calculating Image Size and Projection
Distance

Use the formulas below either to find out how large your
image will be when you know the distance from the projector
to the screen, or to find out how far from the screen to place
the projector if you want an image of a certain size. Since the
size of the image can be changed by rotating the zoom ring,
formulas are given for calculating both the minimum and
maximum sizes.

Note: The formulas given here are for when the projector is placed
flat, without tilting it up at the screen. If you tilt it up by
extending the feet or use electronic keystone correction, your image
size may vary.

Standard Lens

To determine the diagonal size of an image (in inches) when
you know the projection distance:

Maximum diagonal size =

(((2.54

×

projection distance) / 100)

×

36)

+

2.13

Minimum diagonal size =

(((2.54

×

projection distance) / 100)

×

26.84)

+

1.29

To determine the projection distance (in inches) when you
know the diagonal size of the screen image:

Maximum projection distance =

(((diagonal size – 1.29) / 26.84)

×

100 / 2.54

Minimum projection distance =

(((diagonal size – 2.13) / 36)

×

100 / 2.54

Middle Throw Lens (V12H004M03)

To determine the diagonal size of an image (in inches) when
you know the projection distance:

Maximum diagonal size =

(((2.54

×

projection distance ) / 100)

×

27.42)

+

1.49

Minimum diagonal size =
(((2.54

×

projection distance) / 100)

×

20.48)

+

1.1

To determine the projection distance (in inches) when you
know the diagonal size of the screen image:

Maximum projection distance =

(((diagonal size – 1.1) / 20.48)

×

100 / 2.54

Minimum projection distance =

(((diagonal size – 1.49) / 27.42)

×

100 / 2.54

Long Throw Zoom Lens (V12H004L05)

To determine the diagonal size of an image (in inches) when
you know the projection distance:

Maximum diagonal size =

(((2.54

×

projection distance) / 100)

×

20.4)

+

1.93

Minimum diagonal size =

(((2.54

×

projection distance) / 100)

×

15.23)

+

1.45

To determine the projection distance (in inches) when you
know the diagonal size of the screen image:

Maximum projection distance =

(((diagonal size – 1.45) / 15.23)

×

100 / 2.54

Minimum projection distance =

(((diagonal size – 1.93) / 20.54)

×

100 / 2.54

2.5 to 3.5 ft

5.3 to 7.2ft

27 to 36.5 ft

approx. distance

from 60” screen

TBD

Overhead View

Projector

Screen

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