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Author Topic: Projector Horizontal Lens Shift  (Read 7603 times)

Eric Madson

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Projector Horizontal Lens Shift
« on: September 03, 2010, 09:50:05 am »

I am trying to determine the amount of Horizontal Lens shift I can do before I get into Key stoning. Most manufacturers list this as a % but Sanyo lists it as a ratio. I have a job that was specified by a consultant so I am limited to this projector. I have called Sanyo and talked to a Rep and Engineer and received different answers every time. I am trying to verify if this projector/Lens will work or do I need to substitute.


Sanyo Projector---PLC-XP200L
Lens required---LNS-T32
Throw Distance---43’6”
Image size---81x108”
Horizontal Offset of 3’4” between projector and center of screen(Only place it can be mounted.)
Projector Specifications---Up/Down Ratio= 10:0-1:1  Lt/Rt=3:2-2:3 dependent on Lens
No Lt/Rt ratio stated for Lens
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Eric Madson-CTS
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Milt Hathaway

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Re: Projector Horizontal Lens Shift
« Reply #1 on: September 03, 2010, 11:35:38 am »

First off, the "dependent upon the lens" part: One source I found ( http://www.avpartsmaster.net/catalog/index.php?main_page=pro duct_info&cPath=459_487&products_id=34888 ) stated that all lenses except the widest one have the 2:3 shift available. I'm guessing the widest one (LNS-W32) is too large to move in the projector, or mounts differently.

Here's a good explanation of the shift ratios that I found: http://198.170.107.84/soundlightingvideo/video_projection_so lution6.html

If I'm calculating correctly, the maximum you'll be able to move the projector horizontally off-center will be approximately 10.8", and not the 40" you need.

If I'm calculating correctly, of course.
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Milt
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Mac Kerr

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Re: Projector Horizontal Lens Shift
« Reply #2 on: September 03, 2010, 11:38:59 am »

Eric Madson wrote on Fri, 03 September 2010 09:50

I am trying to determine the amount of Horizontal Lens shift I can do before I get into Key stoning. Most manufacturers list this as a % but Sanyo lists it as a ratio. I have a job that was specified by a consultant so I am limited to this projector. I have called Sanyo and talked to a Rep and Engineer and received different answers every time. I am trying to verify if this projector/Lens will work or do I need to substitute.


Sanyo Projector---PLC-XP200L
Lens required---LNS-T32
Throw Distance---43’6”
Image size---81x108”
Horizontal Offset of 3’4” between projector and center of screen(Only place it can be mounted.)
Projector Specifications---Up/Down Ratio= 10:0-1:1  Lt/Rt=3:2-2:3 dependent on Lens
No Lt/Rt ratio stated for Lens



What were the different answers you got from Sanyo? Why isn't the consultant responsible for his design?

That is quite a lot of offset. Screen center to edge is only 54" and you need a 40" offset. It is also a relatively long throw though so you may get lucky. I don't understand Sanyo's ratio spec at all. Good luck.

Mac

edit: After reading Milt's post it makes more sense. The 3:2-2:3 means it has the same shift left and right, and that the maximum shift is 20% (1 out of 5).

I think you need a different solution. I'm sure the consultant who spec'd this has a suggestion.  Rolling Eyes
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Brad Weber

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Re: Projector Horizontal Lens Shift
« Reply #3 on: September 03, 2010, 01:27:20 pm »

Mac Kerr wrote on Fri, 03 September 2010 11:38

Why isn't the consultant responsible for his design?
Mac Kerr wrote on Fri, 03 September 2010 11:38

I think you need a different solution. I'm sure the consultant who spec'd this has a suggestion.  Rolling Eyes

The flip side, is everything as the Consultant expected?  I constantly encounter field conditions that are not as expected.

I remember one project where we had a similar issue only to discover that in multiple rooms the General Contractor had installed the screen where it was supposed to be but then installed the drop ceiling area where the projector was mounted shifted from where it was shown on the drawings.  In another space on the same project without consulting me the Architect decided the screen needed to be centered on the wall rather than centered on the enclosure that had been built for the projector.  Both situations caused horizontal shift issues and both are examples of the 'stuff' that happens on projects during construction over which neither the AV Consultant or AV Contractor sometimes have control.
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Brad Weber
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Eric Madson

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Re: Projector Horizontal Lens Shift
« Reply #4 on: September 03, 2010, 01:47:18 pm »

I have had one Sanyo Tech Rep tell me it was 21.6" Left or right of center for a total of 43.2" of shift. One tech tell me it was 21.6" in from Left or Right edge. The Rep told me 10.8" Left or Right of Center. I came to the conclusion it was 4/10 total or 20% Left or right of center.

The installation is a ornate room with plaster carvings and extreme changes in Ceiling heights. The owner required the projector to be hidden when not used so the consultant specified a Orbiter mount. The only flat ceiling space in the room is the entry way that is along one wall. I am essentially 2 feet from an exterior wall and the consultant specified a 108"x 81" image with a painted screen. If the math is right I can only provide a 70"x54" image. I will submit to the Consultant either a change in Image size or approval for Key Stone correction which should gain me another 20-30" of Image. That way it is on his plate.

Thanks for the affirmations
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Eric Madson-CTS
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Brad Weber

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Re: Projector Horizontal Lens Shift
« Reply #5 on: September 03, 2010, 05:34:05 pm »

Eric Madson wrote on Fri, 03 September 2010 13:47

I have had one Sanyo Tech Rep tell me it was 21.6" Left or right of center for a total of 43.2" of shift. One tech tell me it was 21.6" in from Left or Right edge. The Rep told me 10.8" Left or Right of Center. I came to the conclusion it was 4/10 total or 20% Left or right of center.

Have you tried the projection calculator on Sanyo's web site?  It seems to show the rep being right but I can see how 10.8" left of center or 10.8" right of center might be noted as 21.6" left or right.

Eric Madson wrote on Fri, 03 September 2010 13:47

The installation is a ornate room with plaster carvings and extreme changes in Ceiling heights. The owner required the projector to be hidden when not used so the consultant specified a Orbiter mount. The only flat ceiling space in the room is the entry way that is along one wall. I am essentially 2 feet from an exterior wall and the consultant specified a 108"x 81" image with a painted screen. If the math is right I can only provide a 70"x54" image. I will submit to the Consultant either a change in Image size or approval for Key Stone correction which should gain me another 20-30" of Image. That way it is on his plate.

Based on Sanyo's online calculator, I don't see any problem creating a 108"x81" image with a PLC-XP200L and the 43'-6" throw distance and LNS-T32 lens noted, it looks like anything from an 87"x66.35" to 124.4"x93.3" image is possible.  And I don't believe that the image size will change the lens shift as it is a shift from center, so I'm not sure how that would change anything.

Did the Consultant show a projector location and is that where you are proposing installing it?  Is the screen located where it was supposed to go?  A difference of 3'-4" between the screen and lens horizontal center lines seems like it is something that would have been pretty obvious.
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Brad Weber
muse Audio Video

Eric Madson

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Re: Projector Horizontal Lens Shift
« Reply #6 on: September 07, 2010, 10:26:14 am »

The issue is not can it do the image size but the fact that I am 2' from a wall and shooting parralel to that wall. This limits my size of the image by the amount of Horizontal shift. I have usd projectors with +-75% Horizontal shift so it did not raise immediate flags. I did not specify it but I should have been more dilegent about it.
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Eric Madson-CTS
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Brad Weber

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Re: Projector Horizontal Lens Shift
« Reply #7 on: September 07, 2010, 11:29:15 am »

Eric Madson wrote on Tue, 07 September 2010 10:26

I have usd projectors with +-75% Horizontal shift so it did not raise immediate flags.

What projectors offer that much horizontal lens shift?
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Brad Weber
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Eric Madson

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Re: Projector Horizontal Lens Shift
« Reply #8 on: September 07, 2010, 11:44:26 am »

Christie WX& LX Series
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Eric Madson-CTS
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Brad Weber

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Re: Projector Horizontal Lens Shift
« Reply #9 on: September 07, 2010, 01:14:07 pm »

Eric Madson wrote on Tue, 07 September 2010 11:44

Christie WX& LX Series

The WX series does seem to allow for significant horizontal and vertical offset, however you have to be careful in understanding their definition of offset as it is apparently not the same as shift.  75% offset does not mean that the projector could be offset by 75% of the image width but rather than it can be offset by 75% of the distance from the centerline to the edge of the image, or one half what might be assumed if viewed as a shift value.  Thus for the 108"x81" image noted the projector could be 40.5" off to the side.

The online information for the LX505, LX700, LX1000 all show +/-50% vertical and 10% horizontal shift.  In this case it apparently is shift and thus for the 108"x81" image the projector could be up to 10.8" horizontally off the image centerline.  Not surprisingly, that also seems to be the exact same shift as the Sanyo you are dealing with allows.

I think Christie does need to verify the information they show for the LX605 and LX1500.  The LX605 online specs state "Offsets: Horizontal - 50%*; Vertical - 10%*" and the brochure references that same 50% horizontal and 10% vertical offsets.  However, Page 17 of the LX605 manual contradicts that information and instead defines a 50% vertical and 10% horizontal shift, which makes much more sense.  Similarly, the online specs and brochure for the LX1500 indicate a "Horizontal and vertical offset up to 120% vertical and 78% horizontal (depending on lens)" while Page 18 of the LX1500 User Manual again disagrees and again indicates a 50% vertical and 10% horizontal shift.

This doesn't fix your problem but I think you'd have the same basic problem with many other projectors, although the Christie WX series projectors do seem to be able to allow more image shift for most of the available lenses.
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Brad Weber
muse Audio Video
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