Benq SP870 Benutzerhandbuch

14 

Positioning your projector  

Eng
lish

How to determine the position of the projector for a given screen size

1.

Select your screen size.

2.

Refer to the table and find the closest match to your screen size in the left columns labelled 

. Using this value, look across this row to the right to find the corresponding average distance 

from screen value in the column labelled 

. This is the projection distance.

3.

On that same row, look across to the right column and make note of the 

 value. This 

will determine the final vertical offset placement of the projector in relation to the edge of the screen.

4.

The recommended position for the projector is aligned perpendicular to the horizontal center of the screen, 
at the distance from the screen determined in step 2 above, and offset by the value determined in step 3 
above.

For example, if you are using a 120-inch screen, the average projection distance is 4416 mm and with a vertical 
offset of 210 mm.
If you place the projector in a different position (to that recommended), you will have to tilt it down or up to 
center the image on the screen. In these situations, some image distortion will occur. Use the Keystone function 
to correct the distortion. See 

 for details.

How to determine the recommended screen size for a given distance

This method can be used for situations where you have purchased this projector and would like to know what 
screen size will fit in your room.
The maximum screen size is limited by the physical space available in your room. 
1.

Measure the distance between the projector and where you want to position the screen. This is the 
projection distance.

2.

Refer to the table and find the closest match to your measurement in the average distance from screen 
column labelled 

. Check that your measured distance is between the min and max distances listed 

on either side of the average distance value.

3.

Using this value, look across that row to the left to find the corresponding screen diagonal listed in that row. 
That is the projected image size of the projector at that projection distance.

4.

On that same row, look across to the right column and make note of the 

 value. This 

will determine the final placement of the screen in relation to the horizontal plane of the projector. 

For example, if your measured projection distance was 4.5 m (4500 mm), the closest match in the 

column is 4416 mm. Looking across this row shows that a 120-inch screen is required. If you can only obtain 
metric sized screens, the listed screen sizes on either side of the 120-inch screen are the 3.0 m (3000 mm) and 3.5 
m (3500 mm) screens.
Checking the min and max projection distance values for these screen sizes indicates that the 4.5 m measured 
projection distance will also fit the 3.0 m (3000 mm) size screen. Be aware that these different screens have 
different vertical offset values.