[AG-TECH] Room Layout

John Shalf jshalf at lbl.gov
Fri Jan 18 11:16:44 CST 2002

Marty Hoag wrote:
>    One other consideration is that many projectors have a built
> in optical keystone correction that requires the project be mounted
> level with the bottom of the projected image (e.g. sitting on a table
> or top of the image (if mounted upside down from the ceiling).  That
> means if you put them on shelves or the back wall at the top of the
> image you would want to mount them upside down.  I haven't used the
> Epson projectors though so I'm not sure what they have.

The epsons are digital keystone unfortunately.  The more
oblique the mount, the more resolution you lose (and you get
really strange moire effects if you have a patterned desktop
:-)  )  The lenses *are* interchangable though, but I don't
know if Epson sells a shift-lens for optical keystone
correction.  They do have good short-throw lenses though for
the very sort of room described here, but it will exacerbate
the keystoning problem with a short throw...

>    Some of the higher end projectors do have OPTICAL corrections
> available.  But beware of the digital keystone corrections and shifts.
> The digital corrections work by shaving off pixels which will look
> very very weird when you try to place the projectors to make a wide
> mural - you will have gaps which are not projected.  Others can
> probably provide more technical information on this.
>    Marty

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