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Constant Width question

post #1 of 15
Thread Starter 
Leaving out the pros and cons of constant width vs constant height I am wondering if the following set-up is possible with any current 1080P projectors:

Setting up the projector for 2.35:1 (say 54 x 127) with an anamorphic lens in place, and proper video processor, and adjusting the proper zoom and focus setting into memory 1 of the projector.

Remove the anamorphic lens and keeping the same throw distance adjust zoom and focus for 16:9 screen 72 x127 and setting into memory 2 of projector.


Could the above be done to automate a constant width setup on a screen 72 X 127 with masking ?
post #2 of 15
With or without the lens, letter boxing of a scope image is constant width. The lens benefits you by allowing you to 100% of the panel for "scope" rather than the 75% used when projecting letterboxing.

What your trying to achieve should work so long as the "scaling" is not forgotten...

Mark
post #3 of 15
Thread Starter 
Correct so I get 100% of the panel by scaling and anamorphic lens for 2:35 and also 100% panel for 16:9, and have a constant width setup.
post #4 of 15
Yes you also have to use a VC lens as well. So how are you going to perform the scaling?

Mark
post #5 of 15
Thread Starter 
Totally confusing on my part, let me try and clarify

Is it possible to set the projector up with an anamorphic lens and scaler for 2.35 at 54x127 and also set if from the same throw distance, remove the anamorhic lens and adjust via Zoom and other projector adjustements to 72x127 image?

In other words 2 independent settings from the same throw distance:
1) anamorphic lens in place scaling a 54x127 image
2) no anamorhic lens and a 72x127 image

Is the above possible?
post #6 of 15
Yes by using a VC lens not a HE lens. The VC lens's "scope" image is set by the width and vertically compresses the height, so you can achieve exactly your posted dimensions.

Your throw will not change, just the image height at the 16:9 beam will be reduced to 67% of the height when it is in place...

Mark
post #7 of 15
Thread Starter 
Mark:

Thanks, the above is not possible with a HE compression lens and adjustments?
post #8 of 15
HE stands for Horizontal Expansion and is used for CIH. You need a Vertical Compression lens to do CIW...

Mark
post #9 of 15
Thread Starter 
Mark:
Thanks again so to do constant width with a 72 x127 16:9 screen I would move a Vertcal Compression lens in place and scale for 2:35 Scope 54x127, and by simply removing the lens from the equation I would have full resolution 16:9 @ 72x127, with no zooming nor scaling required ?.

I understand this is the Constant Image Height forum, is it possible to have a sub forum for the few who are interested in discussing Constant Width or Constant Area?
post #10 of 15
Quote:
Originally Posted by LJG View Post

Mark:
Thanks again so to do constant width with a 72 x127 16:9 screen I would move a Vertcal Compression lens in place and scale for 2:35 Scope 54x127, and by simply removing the lens from the equation I would have full resolution 16:9 @ 72x127, with no zooming nor scaling required ?.

You still need scaling, but no zooming is required for what you want to do. You simply remove the lens for 16:9...

Quote:


I understand this is the Constant Image Height forum, is it possible to have a sub forum for the few who are interested in discussing Constant Width or Constant Area?

You need to email Alan with that one...

Mark
post #11 of 15
Thread Starter 
Quote:
Originally Posted by CAVX View Post

You still need scaling, but no zooming is required for what you want to do. You simply remove the lens for 16:9...

Mark

This is where I am lost why would I need to scale a 16:9 Image for a 16:9 projector on a 16:9 screen?

Lon
post #12 of 15
You don't, but you need to scale for "scope" when you move the lens in place or the image will look "short and fat" with a VC lens...

Mark
post #13 of 15
Thread Starter 
Correct I think I got it, with VC lens in place scale for scope, with VC lens removed 16:9 without scaling or zooming!!
post #14 of 15
Quote:
Originally Posted by LJG View Post

Correct I think I got it, with VC lens in place scale for scope, with VC lens removed 16:9 without scaling or zooming!!

Your've got it...

Mark
post #15 of 15
This is what I have.

I have a vertical compression anamorphic lens in front of my Optoma HD70 PJ on a hinge.
When I want to watch 2.35:1 movies, I just pop the anamorphic lens in place, select the LBX mode on the PJ which vertically stretches the image which removes the black top and bottom borders and the lens vertically squeezes the image to the correct aspect ratio.

When I want to watch standard 16:9 movies, I just unhinge my anamorphic lens, select 16:9 mode on the PJ and i've done.

Hope this helps.
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