Arfa Daily wrote:
Not really a repair thing - just a comment on product uselessness really. My
next door neighbour treated himself to a bunch of home cinema gear this
Christmas, including a Panasonic DVD player, a Panasonic DVD / HDD recorder,
a Yamaha digital sound projector, ( whose performance is unbelievably good )
and the crowning glory, Panasonic's latest all singing and dancing front
projector with enough output to work in virtual daylight. All OK so far. He
came round to see me the day after Christmas, bearing bottles of beer - so
that was OK - and wanted me to go round so that he could show me his home
cinema that he had built. As we were walking back round, he told me that the
only problem that he had, was a keystone-distorted picture in the
horizontal. No problem, I told him. There will be menu settings for N-S and
E-W keystone correction. No, he said, there's only one. I told him that he
must be mistaken, as they would not just put one correction in, as it's so
easy for them to distort the image within the projector, to compensate for
optical misalignment.

However, he was right. There is electronic compensation for up-down tilt of
the projector - and the range is huge. You could literally stand the
projector on the floor pointing up at the wall by 30 degrees, or likewise,
down by the same amount from the ceiling, but there is no way to correct for
the one foot !! horizontal misalignment that he was forced to have because
of the only places that the screen and projector shelf could go. Suspension
from the ceiling to place the projector exactly in front of the screen was
not an option. There is a mechanical lever on the front, which shuffles the
lens about, and moves the image around, but this in no way allows you to
compensate for the trapezium shaped picture that is a result of this
comparitively small misalignment. Just how crap is that ?? Considering that
this unit is designed for use in the home, where alignment conditions are
very likely to be less than optimum, just what were the designers thinking
of, when they left this important geometry adjustment out ? Perhaps I'm
missing something, but I don't think so. Both myself and my neighbour spent
a long time reading the book of words, and could find no references to any
correction that could be made in respect of this type of image distortion.
If anybody can enlighten me as to anything different, I'd be really glad to
hear what you have to say ...

Arfa



(In an LCD projector, there is no magnetic N-S correction.) Granted,
trapezoidal distortion is annoying, but it's ridiculously easy to
compensate for. If the projector is already fixed into position and
can't be moved, a relatively minor correction in the *angle* of the
screen will do it. Simply move the side of the screen where the image
is larger slightly closer to the projector. Usually an inch or two will
do it.

This was an error in installation, which even a novice installer should
have corrected for. The keystone correction is only for convenience.
It's rare for there to be an instance where it's acceptable to place the
projector vertically level with the center of the screen, without
affecting sight lines. That's why there's some method of keystone
correction in nearly every projector. Getting it in the middle
*horizontally* should be a given...and trivial to achieve.

Electronic geometry corrections affect the resolution available anyway,
as pixels are sacrificed for geometry. Optical or mechanical (moving
the screen or optics) solutions offer the highest degree of accuracy,
resolution and viewability.

Given that he's spent so much on gear, it would make sense to install it
all correctly. If he had it done, he needs to get the installers out to
correct it. If he did it himself....

jak