# Benq W1070 ceiling mount...



## Rairun (Dec 9, 2010)

Hi people,

I have a simple question:

I will mount Benq W1070 on ceiling. And i want the projected image to be close to ceiling as much as possible. So, if my screen is 100", %10 of screen height is 5", which is the minimum offset for the given size.
This means that the distance between lens center and top of my screen can not be less than 5". Is this correct?

Btw, on the chart of W1070's user manual (page 16), minimum offset/highest lens position for 100" is shown as 62mm. I don't get how it's calculated.

Thanks!


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## NBPk402 (Feb 21, 2012)

Rairun said:


> Hi people,
> 
> I have a simple question:
> 
> ...


The BenQ w1070 is awkward to setup... I would mound the projector as close to the ceiling as possible, and then mount the screen as the lens shift is very minimal.


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## Yiannis1970 (Sep 2, 2012)

Rairun said:


> Hi people,
> 
> I have a simple question:
> 
> ...


There's a slight error on your calculations. If your screen is 100'' that means is 100'' in diagonal and not on vertical axis (screen height). Offset is calculated by screen height. Practically, 1070 will stand ~6 cm above your screen. I believe though that if you have a ceiling high enough (let's say 2,70 meters) and follow this path (projector as close as possible to the ceiling) your image will result probably uncomfortable because it will be over 1,5 meters off the ground.


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## Rairun (Dec 9, 2010)

If the screen has 16:9 aspect ratio and 100" diagonal size then the screen height is 50" (49 exactly). I calculated the offset using the height: 50x0.1=5 inch. I don't understand what's wrong with this calculation. And i don't know how you get 6cm.

Yes, that's true, the screen will be too high. Because my room has a limitation: The projector screen has to be installed above and a little behind my computer desk. Which means the screen's bottom edge has to be higher than the lcd monitor, loudspeakers and studio monitors. There is no better place to put the screen. But my cinema couch's back can be tilted, so i'll be viewing while leaning back, which saves me raising my head too much.

With this situation, i consider tilting the screen a bit downwards (and the projector upwards of course). I'm not sure if this would make the viewing more comfortable though...


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## Yiannis1970 (Sep 2, 2012)

Rairun said:


> If the screen has 16:9 aspect ratio and 100" diagonal size then the screen height is 50" (49 exactly). I calculated the offset using the height: 50x0.1=5 inch. I don't understand what's wrong with this calculation. And i don't know how you get 6cm.
> 
> Yes, that's true, the screen will be too high. Because my room has a limitation: The projector screen has to be installed above and a little behind my computer desk. Which means the screen's bottom edge has to be higher than the lcd monitor, loudspeakers and studio monitors. There is no better place to put the screen. But my cinema couch's back can be tilted, so i'll be viewing while leaning back, which saves me raising my head too much.
> 
> With this situation, i consider tilting the screen a bit downwards (and the projector upwards of course). I'm not sure if this would make the viewing more comfortable though...


6.2 cm i get from projector's manual on page 16. You can check it out if you wish.

As far as it concerns offset, Infocus gives a nice and handy explanation of how it works here:

http://www.hcinema.de/pdf/infocus-in72-74-76-offset-en.pdf

The above pdf shows the offset of a fixed lens without the use of lens shift. 1070 has a small range on it's lens shift (around 10%), therefore on a 100'' (125 cm in height) you can move your image up or down for ~12,5 cm.

Furthermore for positioning, if you tilt as you say screen and projector, you will destroy the geometry of the image having a terrible impact on sharpness (it's a mechanical way to use the keystone button...). Screen and projector must be in parallel position to each other and in absolute vertical position from the ground.


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## Rairun (Dec 9, 2010)

Thanks a bunch!


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