BenQ W770ST user manual Obtaining a preferred projected image size

Obtaining a preferred projected image size

The distance from the projector lens to the screen, the zoom setting, and the video format each factors in the projected image size.

The projector should always be placed horizontally level (like flat on a table), and positioned directly perpendicular 90° right-angle square) to the screen. This prevents image distortion caused by angled projections (or projecting onto angled surfaces). If the projector is mounted on a ceiling, it must be mounted upside-down.

If the projector is positioned further away from the screen, the projected image size increases, and the vertical offset also increases proportionately.

When determining the positions of the screen and projector, you will need to account for both the projected image size and the vertical offset dimension, which are directly proportional to the projection distance.

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

1.Determine the aspect ratio of your screen, 16:9 or 4:3?

2.Refer to the table and find the closest match to your screen size in the left columns labelled "Screen dimensions". Using this value, look across this row to the right to find the corresponding average distance from screen value in the column labelled "Average". This is the projection distance.

3.Decide the exact position of your projector according to the position of your screen and the adjustable lens shift range.

<Example>

W750: If you are using a 120-inch, 4:3-aspect-ratio screen, please refer to "The screen aspect ratio is 4:3 and the projected picture is 16:9". The average projection distance is 3512 mm.

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.Determine the aspect ratio of your screen, 16:9 or 4:3?

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

3.Refer to the table and find the closest match to your measurement in the average distance from screen column labelled "Average". Check that your measured distance is between the min. and max. distances listed on either side of the average distance value.

4.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.

<Example>

W750: If you have a 16:9-aspect-ratio screen and your measured projection distance was 4500 mm, please refer to "The screen aspect ratio is 16:9 and the projected picture is 16:9". The closest match in the "Average" column is 4464 mm. Looking across this row shows that a 140-inch screen is required.

Checking the min. and max. projection distance values in the columns of "Projection distance <D> [mm]" on page 15 indicates that the 4500 mm measured projection distance will also fit the 130 and 150-inch size screens. The projector can be adjusted (using the zoom control) to display on these different screen sizes at the projection distance. Be aware that these different screens have different vertical offset values.

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 "Correcting picture distortion" on page 27 for details.

14 Positioning your projector