Panasonic projector ...

[Arfa Daily]

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

 

[jakdedert]

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

 

[jakdedert]

(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

Okay...rereading the OP, I see where he was forced to put the projector
off-center. In that case, changing the angle of the screen is required.
Some forethought in the installation might have produced a projector
which would have filled the screen from a closer distance--possibly
allowing center placement--but he's locked in now. Angle one side of
the screen (the one with the large side of the trapezoid) toward the
projector. Depending on the degree of distortion, the distance from
screen to projector, the size of the image desired and the screen
mounting method, it might yet be a trivial fix...but it must be done to
obtain a 'square' image.

This is an instance in which professional consultation might have saved
money. I've seen few projectors with trapezoid correction.

jak

 

[Arfa Daily]

Okay...rereading the OP, I see where he was forced to put the projector
off-center. In that case, changing the angle of the screen is required.
Some forethought in the installation might have produced a projector which
would have filled the screen from a closer distance--possibly allowing
center placement--but he's locked in now. Angle one side of the screen
(the one with the large side of the trapezoid) toward the projector.
Depending on the degree of distortion, the distance from screen to
projector, the size of the image desired and the screen mounting method,
it might yet be a trivial fix...but it must be done to obtain a 'square'
image.

This is an instance in which professional consultation might have saved
money. I've seen few projectors with trapezoid correction.

jak

Hi Jak

I hear what you are saying, and of course in an ideal world, the projector
would be directly in front of the screen, but in the real world, this may
not be possible - hence the point that I was making that as this is intended
as a domestic projector, where compromises are highly likely to have to be
made to accommodate it in an existing house room layout, rather than a
professional unit that is likely to be installed in a custom built lecture
theatre or whatever, it would have been prudent to have built in the
necessary correction. Considering that such a huge range of correction on
this unit is readily available for vertical keystoning correction, it would
not have been that difficult to have incorporated similar, if limited,
compensation for any horizontal positioning error, given of course that this
will affect resolution to a degree, as you point out.

My neighbour did install it all himself, but he is far from a dumb person.
Apart from this minor problem, it all works exactly as he intended, which
given the range of equipment that he now has connected together, including a
VCR and Sat box, as well as his new players and recorders, is in my opinion,
no mean feat ( he is an electrician by trade, but a director of a metal
plating company these days ). As far as tilting the screen goes as a method
of correction, of course this is the obvious way of doing it, and we had
figured that. However, again in this instance, this isn't possible, as his
screen is, for the moment, a white painted wall which, before everyone
starts howling that this is not reflective enough or not a pure enough
white, or whatever, actually does work very well.

The problem is on the way to being solved now, in that he has effectively
turned the room layout through 90 degrees, which has allowed him to mount
the projector directly in front of the screen ( a different white painted
wall ... ) However, this has meant a considerably more difficult run of the
cables, and longer HDMI runs etc, which is what he was trying to avoid in
the first place.

On the subject of correction in both directions, I have been involved with a
couple of professional installations, but from the audio installation side
rather than from the visual angle. I can't remember what projector types
they were, but they were supplied by the friend who was responsible for the
job, and who hired me in for the audio work. What I do remember, however,
was that in one of the installations, the projector was actually up in a
proper booth in a hospital lecture theatre, and was offset to the side of
the screen. The projector in question had electronic adjustments for
keystone and trapezium distortion via the remote handset, so the offset did
not represent any problem at all, as I had expected it wouldn't for my
neighbour.

Arfa

 

[jakdedert]

Arfa Daily wrote:

The problem is on the way to being solved now, in that he has effectively
turned the room layout through 90 degrees, which has allowed him to mount
the projector directly in front of the screen ( a different white painted
wall ... ) However, this has meant a considerably more difficult run of the
cables, and longer HDMI runs etc, which is what he was trying to avoid in
the first place.

Considering the amount of money already spent on equipment--not to
mention the time involved--he might have been better served by
purchasing a screen which he could have oriented in the correct plane.
I don't know what they cost on your side of the pond, but used ones are
really cheap on eBay here (seller ID: 'avforsale' has a variety every week).

He would have also gained considerably in brightness and contrast.
Despite how good it looks now, if it's merely a painted wall (excepting
special paints made for the purpose, which are available), the
improvement would have been striking.

On the subject of correction in both directions, I have been involved with a
couple of professional installations, but from the audio installation side
rather than from the visual angle. I can't remember what projector types
they were, but they were supplied by the friend who was responsible for the
job, and who hired me in for the audio work. What I do remember, however,
was that in one of the installations, the projector was actually up in a
proper booth in a hospital lecture theatre, and was offset to the side of
the screen. The projector in question had electronic adjustments for
keystone and trapezium distortion via the remote handset, so the offset did
not represent any problem at all, as I had expected it wouldn't for my
neighbour.

I suspect that to find one with the proper correction would have cost a
good deal more. It's pretty rare on lower end gear (lower end being
consumer vs. pro). Even at that, if his supplier takes returns, he
might have been able to swap projectors. I still feel a proper screen
would have been his best bet.

In most cases, the amount of correction is hardly noticeable to viewers.
When I install projectors in meeting rooms (daily, in some of my job
assignments), I often just 'tap' the tripod supporting the screen with
my toe in order to correct a trapezoid, rather than reposition the
projector.

jak

 

[Arfa Daily]

Considering the amount of money already spent on equipment--not to
mention the time involved--he might have been better served by purchasing
a screen which he could have oriented in the correct plane. I don't know
what they cost on your side of the pond, but used ones are really cheap on
eBay here (seller ID: 'avforsale' has a variety every week).

He would have also gained considerably in brightness and contrast. Despite
how good it looks now, if it's merely a painted wall (excepting special
paints made for the purpose, which are available), the improvement would
have been striking.

I suspect that you are probably right, but 20 / 20 hindsight is a wonderful
thing, ain't it ?

d;~}

Arfa