Throw Distance - JVC DLA-G20 Sales Manual

Throw distance

Obtaining a rough throw distance
If you do not have a handy copy of the table, "Relationship between screen size and throw distance", you can get a rough
estimate using the following method.
Projection ratio of the projection lens
Since the DLA-G20 incorporates a zoom lens, throw distance and projection screen size can be adjusted. Indications
marked on the projection lens (such as 3:1) represent the "projection ratio", that is, "throw distance: screen width". When
the screen width is "1", the throw distance is "3".
What does the lens projection ratio
"3:1" mean?
Throw distance = 3
Obtaining the screen width
When the projector screen size is shown in inches (diagonally) and the screen width is unknown, use the following formula.
4:3
Screen width (m) =
16:9
Screen width (m) =
Using this formula, the inch value (diagonally) can be calculated.
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Screen width = 1
Inch value (diagonal)
49.21
Inches (diagonal)
45.18
Obtaining the rough throw distance
Once you have calculated the screen width (as shown on the previous page), you can obtain a rough estimate of the throw
distance.
Rough throw distance = screen width
Calculation example
Precondition
Screen size: 100" (4:3)
DLA-G20: Zoom lens projection ratio 2:1 to 3:1
Calculation
Screen width = 2.03 x 2 = 4.96 (m), 2.30 x 3 = 6.09 (m)
This calculation shows that a throw distance of between
4.06 and 6.09 m is required to project an image on a 100"
(4:3) screen with the DLA-G20.
Keep in mind that the value obtained with this formula is
approximate.
• Do not use the value without making allowance for error.
• Use this value as a guide when first discussing what
screen size should be selected.
• If you need the correct value, refer to the table,
"Relationship between screen size and throw distance" on
pages 18 to 21.
D-ILA Method Present Condition and Subject
Throw distance
lens value
Selecting the screen size
To determine the appropriate screen size, refer to the table
below. The approximate relationship between screen size
and number of seats is based on data from existing
installations.
Screen size (model) Number of seats
60 ~ 10
80 10 ~ 20
100 20 ~ 30
120 30 ~ 80
150 80 ~ 120
200 120 ~ 200
250 200 ~ 450
• Since the DLA-G20 is provided with a zoom lens, there is
more flexibility with regards to installation position.
However, the throw distance must also be taken into
consideration when choosing the installation position;
otherwise, the required picture size may not projected.
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