How is the projector mounted?
Have a look how level / straight the projector is. From what I know, the best way to have a projector mounted is to ensure that you have to use very minimal keystone (trapezoid adjustment). To do this making sure that the projector itself is level by using a spirit level, and then taking other measurements to ensure that it is squarely located so that the center of the projector glass matches up with the center line of the projector screen / wall. You can also get at Bunnings (or most other hardware places around the world) a 3 way spirit level which can be used for ensuring posts are straight and level - it is pretty easy to attach this to the side of the projector when adjusting it to make sure its all OK.
For my setup, as I have an AE700, this meant off setting the actual projector mount to the left of center of the screen so that the middle of the glass lined up. I also dropped the projector down so that the middle of the glass was level with the top of the screen area.
As a result, I dont have to use any lense shift, and only 2 points of keystone adjustment to make sure the image is all nice and square.
Just remember - keystone & using tilt shift reduce your picture quality - try to eliminate using it as much as possible.
Have a look at page 16/17 of this PDF for an illustration of what I am talking about (
http://service.us.panasonic.com/OPERMANPDF/PTAE700U.PDF)
Hope this helps.
