Panasonic projector ...

(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

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

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

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 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

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

d;~}

Arfa