Help. HD 81

[georgev]

Hi, I am planning to install my new HD 81.
My screen is 2040 by 115, and I have been able to calculate ideal distance from the screen.
What height above the upper level of the screen should the centre of the lens be if I want to avoid any keystone correction?
The image offset of the unit is 136%. In other words how do you calculate image offset in cm or inches.
Is it as staightforward as 36% of the screen height or is there more to it?
Kind Regards,
George.

[George Bellefontaine]

Is it as staightforward as 36% of the screen height ?
Kind Regards,
George.

That is my understanding. But it is best to try the calculation before making a permanent install.

[georgev]

Thanks, so I thought, but when I phoned Optoma South Africa, they gave me a different height. I subesequently phone Optoma UK, who gave me a height closer to the way I think, but different, hence I turned to people in the know. Users like you.
It is amazing how much "wrong" information one can get from event the suppliers themselves.

[George Bellefontaine]

George, sometimes the manufacturer includes offset calculation in their manuals. It seems that the offset will likely be a bit different depending on the distance from the screen and the size of the picture you want to project. Many manuals will show where the lens of the projector should be in relation to the distance and size of the projected image you desire. Be sure to check your manual to see if Optoma has this information.

[georgev]

Thanks George, yes I perused the manual, and there it was.
Distance from the screen x tangent of 6.25degrees(declination angle). This made sense as it would be dependant on the distance from the screen.
Thanks.
What I did do was to get the PJ, mount it and project an image without keystone, and mark it out. Now I have to build my wood panelling around that marked space.
Taking time and effort but hopefully will get the desired result.

[George Bellefontaine]

What I did do was to get the PJ, mount it and project an image without keystone, and mark it out. Now I have to build my wood panelling around that marked space.

I did something similiar the first time I installed a permanent wall screen.