Kind of a general question at this point, but is their any difference in image position/shift range when my RS 640 is shelf mounted (sitting on its four adjustable feet) 5 inches above top of screen as opposed to having it in the same location above the screen, but sitting inverted as it would be with a ceiling mount? I am trying to use lens shift to bring a 2.40:1 image down so that the bottom of the image is even with the bottom of the screen but I do not have enough shift range to accomplish this. I am hoping to use lens memory to have the image at bottom of screen for 2.40:1 images and another memory for a 16x9 image. Consulting the JVC manual did not clarify this for me.
When I did my initial setup with 16x9 image, it seemed that I had to use a lot more lens shift than I expected to get the bottom of the image to line up with bottom of screen. I have done setups with JVC projectors on a coffee table with lens close to bottom of screen and it seems that I am close to the center of the shift range to fit the image to a screen, and same applies when I have used a ceiling mount with the projector inverted and lens center close to the top of the screen.
I cannot lower the shelf position since the projector is in the master BR on the other side of the theaters back wall projecting through a framed opening in the wall. It is mounted as low as possible to clear the top of the BR entry door which is 8 feet tall. Projector is also centered on the screen in it current location. The screen is an SI Solo Pro, mounted to the front wall on wood corbels that allow the screen to extend out enough to clear my 65" Samsung curved TV (I know, curved??? This is a 4K KS9800 which was only available as a curved screen when I bought it) mounted to front wall with a full motion wall mount which closes to about 5 inches away from wall. The Solo Pro clears the retracted TV by about an inch when it is dropped down, with bottom of screen stopping about 2 inches below bottom edge of TV. Screen is 16x9 110" dia, 96"w x 54" high. Projector lens is 17ft 3" to screen surface.
I am assuming that if I invert the projector on the shelf it might fix the problem, but this would not be a suitable option due to the projector being unstable and non adjustable in this configuration. If inverting the projector is a fix, I can use a ceiling mount and nix the shelf mount idea.
Thanks in advance for any insight on this.