Hello,
sorry for yet another question to ask.Am i correct in thinking that a projector (pany 300) has to be mounted dead centre to the screen (1/2X by 1/2Y ) to avoid keystone effect or have i lost the plot altogether.

[tonytigerrr]

Centre in the horizontal yes, but the vertical needs to be about 10cm above the bottom of the screen (desk mounted) or 10cm from the top of the screen (ceiling mounted).

Thanks Tony for both replies!
I think i will buy a manual pulldown 67" width and keep it permanently pulled down, any supplier you would recommend?
Also ref keystone setting, I'm i right in saying that horizontal setting is very important but vertical (10cm below top of screen) is not as crucial?

[tonytigerrr]

depends what you mean by crucial. If the PJ is not positioned 10cm below bottom/top of screen then you will have to tilt it to fill your screen and correct with keystone - a digital process which will degrade picture quality.

Whether this is acceptable in order to give flexibility with PJ position is purely a matter of personal preference. If you're asking whether using keystone in the vertical has less of a degrading effect on the picture than in the horizontal then I dont know, but I dont see why that would be the case.

The lens offset, should be given by the manual or on the manufacturers website. Usually by a percentage of image height. Its good to design in somekind of adjustment though, like a few threaded rods so you can raise or lower the projector if you need to. Horizontally will be smack on. Both are crucial to the alignment, but you are more likely to have internal digital correction for vertical errors rather than horizontal, but some pj's do have both. Just because you have got them though doesn't mean you can skimp on the alignment time!!

Good luck.