## BenQ W750 – A 3D 720p Projector

I wrote this post for myself as a reference when I bought the projector. However, I returned my W750 to Amazon for two reasons: It made a nasty high frequency noise when plugged in to the power mains (while being powered off) and the rainbow effect of the DLP technology was disturbing me too much while watching the first movie with the projector.

### Projection Geometry

My projection canvas is 90 cm x 160 cm big and thus has a diagonal of 183 cm (or 72 inch).

On page 15 of the user manual of the W750 you can find details about how to position the projector to the screen in order to get a proper setup.

I took the data from the table and plotted the data, see the following graphs:

Screen distance vs Screen Diagonal:

Same plot with the axes flipped (Screen Diagonal vs Screen distance):

Formula for the interpolated minimum distance:

screen diagonal in m × 1.141


Formula for the interpolated maximum distance:

screen diagonal in m × 1.369


(throw ratio as listed: 1.31-1.57)

Formula for the interpolated vertical offset:

vertical offset in cm = screen diagonal in m × 0.042 + 0.007


For my screen (1,83 m diagonal) the projector distance thus has to be:

• min: 2,10 m
• max: 2,53 m

and the vertical offset must be 7,6 cm.

In order to get a proper projection, you should not position the projector outside of this region. Also the projector has to be put to a position 7,6 cm above (or below) the upper (lower) edge of the screen in order to get a projection without distortions. If you put it at a different vertical offset, you have to correct for that using the setting menu of the projector (Keystone correction) at the cost of sharpness and quality of your projected content.

### Geometric Projection Setup for W770ST

The same plots as shown above but adopted to the W770ST:

Screen distance vs Screen Diagonal:
Same plot with the axes flipped (Screen Diagonal vs Screen distance):

### Resources

BenQ W750 Product Web Page:

RS-232 control port:

Manual:

geizhals.at/de (German best price search engine):

3D glasses