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Discussion Starter · #1 ·
Is it possible to do CIH with a lense if your projector is offset from center?


My mounting force me to have the projector offset to the left in order to clear a column that my builder happily left right in the middle of my room. I have been fine just using the optical offset available on the RS1 to mount adjacent to the column. Curious if it's even possible to add a lense in this arrangement?
 

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From Panamorph website:


The use of horizontal lens shift (shifting the image side to side) is NOT recommended because it will create "keystone" distortion.
 

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Quote:
Originally Posted by zamboniman /forum/post/15575445


Is it possible to do CIH with a lense if your projector is offset from center?


My mounting force me to have the projector offset to the left in order to clear a column that my builder happily left right in the middle of my room. I have been fine just using the optical offset available on the RS1 to mount adjacent to the column. Curious if it's even possible to add a lense in this arrangement?


It is possible. In that case the lens has to be rotated to the direction of beam, exactly similarly as in case of vertical offset. If the prisms are adjustable the horizontal offset is possible to be compensated even without rotating the lens.
 

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I highly recommend making every effort to set up the projector and screen to minimize all geometric distortion prior to attempting to install and align the lens.


Although it maybe possible to compensate for projector installation position errors, the visual effects caused by projector/screen miss-alignment interact with lens/projector alignment. This makes lens alignment and troubleshooting difficult and time consuming.


When installing my anamorphic lens I was having alignment issues unitil I removed all keystone correction and leveled the projector relative to the screen to minimize vertical keystoning. Then everything just fell into place.
 

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Set up your projector (without the A-lens) centered on the spot you need it to be centered to. Use only offset to get there (don't tilt or yaw the case of the projector... have it pointing square on to the plane of the screen).


Then you slide the A-lens into place and line it up so that the centre of the projector beam passes exactly through the center of and the A-len's cylindrical elements or prisms. This means some tilt and yaw, or both, plus vertical or horizontal offset (or both) will have to be introduced to the A-lens. You line the A-lens up with the axis of the beam of the projector, so that the center of the image passes through the center of the A-lens. This line up may not end up with your A-lens necessarily perpendicular to the projector case. Don't worry about that. It's the beam you're adjusting to, not the casework of the projector.


It's fairly easy to do this if you have an adjustable mount. It works fine. I've never been able to figure out why Panamorph recommend against this. I've always had a severely offset setup - two feet to the left of centre and 2 feet above it, and my picture qgeometry is fine, free of keystoning (although I do use a cylindrical).
 

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Discussion Starter · #7 ·
thanks guys.... maybe there is hope after all



Being that the lens is such an investment it's too expensive for an "experiment".. it'd be really nice to get ahold of one to try out to see how well it would work in my case and if the end result would be acceptable.... but in the $G's without a sure thing and great performance that's just not happening... need to find local lense that will travel
 

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John I can bring by my lens to try I do not think it is ideal for the size beam you have but it may work for a test fit.


Nate
 

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Discussion Starter · #10 ·
awesome offer Nate. Is your lense HE or VC? I'm thinking HE is the way to go not sure if this would matter for the test? Might be worth a shot either way...
 

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It is a VC but for just the test to see how far off it is should not matter. I like the VC and leave it in place all the time just use scaling to get the correct image. Very little 16/9 stuff.


Nate
 

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So your projector being off axis - is that horizontally or vertically off axis?
 

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Zamboniman,


Maybe a new house is the better option. There are plenty coming on the market in the NW suburbs.
 

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Discussion Starter · #16 ·
same exact response the wife has given me over and over and over....... quit shoehorning stuff into this house and look at the bigger picture/different house


unfortunately there is a lot of blood and sweat into the current room... but given the chance to do it all over my oh my what I'd do different.. but that said... not sure where I'd find the $$$ to do that either???
 

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I am the same way was holding out for a new house for a better room with more space...well i am still here and well just knocked some walls out to do it the way I want it. Still could use more width but have to make due with what I have for now. HT 2.0


Nate
 

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Quote:
Originally Posted by prismasonic /forum/post/15591896


It is possible. In that case the lens has to be rotated to the direction of beam, exactly similarly as in case of vertical offset. If the prisms are adjustable the horizontal offset is possible to be compensated even without rotating the lens.

Anssi,


That is why I like you lens design. You can make slight adjustments in stretch and offset. None of the other lower or higher end units can do this!


Charles
 
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