Help me understand optical keystone

[spaceape]

I have a question regarding my projector image. My projector are very slightly angled down and therefore produce a trapezoid image. But this is almost entirely happening on the left side only going from bottom too top becoming more and more pronounced in that direction.

Why is this? Shouldn't the right side be affected too?

[frogmort]

If the left side of the image is smaller than the right, it sounds like you need to turn(rotate) your projector to the left a little(while facing the screen), then use your horizontal lens shift to bring the image back to the right, to get it back on the screen. That should help fix the problem.

Sorry, if this is not the right answer, at least I'm bumping it back to the top of the home page for others to see. A picture of what it looks like might also make it easier for people to understand your problem better.

[spaceape]

Originally Posted by frogmort

If the left side of the image is smaller than the right, it sounds like you need to turn(rotate) your projector to the left a little(while facing the screen), then use your horizontal lens shift to bring the image back to the right, to get it back on the screen. That should help fix the problem.

Sorry, if this is not the right answer, at least I'm bumping it back to the top of the home page for others to see. A picture of what it looks like might also make it easier for people to understand your problem better.

Yes that's properly it Joe. Got it.. twisting it. It's just weird that the other sides are level, they usually follow the same rules. Well the right side is a tiny bit off but less so than the left side.

I tried taking pictures pictures but the outside of my projected image is so dark and my camera isn't so good. I can get any shots showing it. The trapezoid "corner" is also very slight making it harder still too capture.

[spaceape]

Alright here goes anyway. Judging from the pictures it seems im a liar and both corners are affected but strangely looking through my own eyes the right side doesn't seem that much effected.







I guess the only remedy is too find a new place for the pj lower down the rear wall.

[frogmort]

Originally Posted by spaceape

Alright here goes anyway. Judging from the pictures it seems im a liar and both corners are affected but strangely looking through my own eyes the right side doesn't seem that much effected.







I guess the only remedy is too find a new place for the pj lower down the rear wall.

Yes, I would guess that if you have your vertical lens shift all the way down as low as it will go and it's still not enough, you probably either need to raise the screen a little bit, or lower the projector a little.

[spaceape]

Originally Posted by frogmort

Yes, I would guess that if you have your vertical lens shift all the way down as low as it will go and it's still not enough, you probably either need to raise the screen a little bit, or lower the projector a little.

I guess i should have thought it over before this happened, but heck we all make mistakes.

Yes the shift is as far down as possible. I've even taken the legs of the pj. Tomorrow i think i'll try raising the screen too see if my neck can handle it.

Thanks Joe.

[crazyBLUE]

Originally Posted by spaceape

I guess i should have thought it over before this happened, but heck we all make mistakes.

Yes the shift is as far down as possible. I've even taken the legs of the pj. Tomorrow i think i'll try raising the screen too see if my neck can handle it.

Thanks Joe.

Tommy.

After looking at your gallery I see no reason why you can't move the mount for the PJ on the wall. This way you can lower it & find center to the screen to eliminate your problem.

A little wall fixing & no one will ever know

[Almadacr]

Like Brent said i would take this road , maybe by lowering the PJ by 6 to 8 inches will do the job .

[spaceape]

Originally Posted by crazyBLUE

Tommy.

After looking at your gallery I see no reason why you can't move the mount for the PJ on the wall. This way you can lower it & find center to the screen to eliminate your problem.

A little wall fixing & no one will ever know

Hi Brent.

Yes i have a little bit of space in that spot. My gallery is old now and lots of things have happened since then. Now i have a shelf like shown below.





I'll try raising the screen first too see if i can accept that because mounting the shelf (or any other thing for that matter) is a pain as i need too drill deep into the brick wall too make it safe. and for that i need special tools and help from a family member that seldom has time off.

[spaceape]

Originally Posted by Almadacr

Like Brent said i would take this road , maybe by lowering the PJ by 6 to 8 inches will do the job .

Thanks for the help. Yes that sure seems like the best solution. Although i only have 3 inches or so before i hit the top acoustic panel.

[spaceape]

[crazyBLUE]

Originally Posted by spaceape

Thanks for the help. Yes that sure seems like the best solution. Although i only have 3 inches or so before i hit the top acoustic panel.

Then move the panel I can understand that it might be a pain to move the shelf ~ But it seems to me you are having a bigger problem getting the picture just right on the screen Lower it & center it ~ Problem solved

[spaceape]

Originally Posted by crazyBLUE

Then move the panel I can understand that it might be a pain to move the shelf ~ But it seems to me you are having a bigger problem getting the picture just right on the screen Lower it & center it ~ Problem solved

Sir Yes Sir.

[frogmort]

Originally Posted by spaceape

Sir Yes Sir.

I've got an idea, since the best solution would be to lower the pj shelf, but the easiest solution would be to raise the screen, why not just temporarily raise the screen a little, until you can get someone to help you lower the shelf, then you can put the screen back where you had it.

Another idea: You could always pay a professional to come out and lower the shelf for you. It would probably only take them less than an hour to do it, so it probably wouldn't cost that much, and it would probably be more stable and level.

Just throwing out ideas to help. I hope you get it taken care of soon.

[crazyBLUE]

Originally Posted by frogmort

I've got an idea, since the best solution would be to lower the pj shelf, but the easiest solution would be to raise the screen, why not just temporarily raise the screen a little, until you can get someone to help you lower the shelf, then you can put the screen back where you had it.

Another idea: You could always pay a professional to come out and lower the shelf for you. It would probably only take them less than an hour to do it, so it probably wouldn't cost that much, and it would probably be more stable and level.

Just throwing out ideas to help. I hope you get it taken care of soon.

That pic kills me

Good suggestions Joe

[Almadacr]

But to raise the Screen he will need someones help to hold on one side and more drilling !!

Cheaper choice get a drill It will take you 10 minutes .

[spaceape]

Thanks for the suggestions guys.

I leveled my projector and raised the screen a bit. Also managed too drop my screen very hard and make a hole in the screen..luckily no damage on the speakers as far as i can see.

Strangely at first with the the zoom out a bit it looked a tad better but not perfect. But after zooming in too the black borders i hardly notice it at all..Im perplexed maybe a projector is always going too have a little bit of this type of thing.

Im debating with myself if i should get a new smaller screen too finally remove the annoyance of having too almost go sideways every time going too the bedroom. or maybe continue using my battered old screen with both horizontal lines and holes in it.

I have my eyes on a cheap 84" pulldown. Should shave of 9cm on each side and still be rather large.

[spaceape]

Latest screens acceptable i think right? Pictures are taking with me sitting and then standing up.