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WestbrookUSA

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
When swapping between 2 Broke Girls and Lord of the Rings, why is it that you must zoom?  On a 2.35 screen, wouldn't Broke Girls just show up at the smaller size?

I'm not understanding WHY you have to zoom when you swap between the AR's.  I must've read every thread I could and I concede defeat.  Please help me figure this out.

My pea brain can't figure it out, if I pick LoTR in 2.35, wouldn't it simply just show at the 2.35 AR?  And if i'm on Broke Girls, wouldn't it just show at the 1.78?  Why do I have to zoom?  Do I have to zoom or am i fundamentally misunderstanding things.

The situation beyond the question: I'm weighing the classic 2.4 v 1.78 for a sony 55es with a 12-13' throw max.  65/35 movies/tv+games.     Good light control.  Like 3d.  Family man, 3 kids.  Reg tv exists for the crap stuff behind the screen. already have speakers and surround sound etc.  pic below is a rev old, the available width is 110" w/ 7'6" ceilings.

(in fact, would i be stuck zooming if i settled for CIW?)

Thanks all, you're the best!

room:

CAVX

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All BDs are based on an AR of 1.78:1. So a film presented as 1.78:1 will be "full screen" and a Scope film will be letterboxed. This means the height of the Scope image is 0.75x that of the 16:9 image.

So as it stands, you must zoom the Scope image to get the image to be the same height.

There are three ways to do Constant Image Height -

A = Zoom method is done by optically expanding the image in both directions (V and H) to make the Scope image the same height. You use your zoom on your projector.

B = Anamorphic Lens + VP. This is a 2 part process that requires electrically vertically stretching the image (AKA Scaling) to fill the image chip, then Optically expanding (in H direction ONLY) the image to restore the geometry using an anamorphic lens.

C = Shrink method. This requires a video processor.

stanger89

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The other part of that is your projector is 16:9, when you line it up so that it fills a 16:9 area, it doesn't fill the 2.35:1 area, to fill the full scope screen, you need to zoom. Then if you show a 16:9 movie, it overspills the screen and you have to zoom smaller to make it fit.

WestbrookUSA

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Hypothetical case:

I have a 2.4 screen and with my 16:9 projector I zoom the image to fit the height. I watch 2 Broke Girls and everybody's happy. Nobody cares about the vertical side black bars.

Then, Daddy puts in Lord of The Rings in 2.4 and blammo the image fills the entire 2.4 screen and I didn't zoom anything.

Is the hypothetical case a correct understanding?

R Harkness

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Quote:
Originally Posted by WestbrookUSA  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24351499

Hypothetical case:

I have a 2.4 screen and with my 16:9 projector I zoom the image to fit the height. I watch 2 Broke Girls and everybody's happy. Nobody cares about the vertical side black bars.

Then, Daddy puts in Lord of The Rings in 2.4 and blammo the image fills the entire 2.4 screen and I didn't zoom anything.

Is the hypothetical case a correct understanding?

Not without using an Anamorphic lens. I think you still haven't got it.

Your projector puts out a natively 16:9 shaped image, always.

Blu-Rays are encoded as 16:9, so the same shape as a 16:9 screen.

But movies as you know have different aspect ratios, some wider than 16:9. Since Blu-Ray has only an exact amount of pixels available for any movie, and those pixels make up a 16:9 shape, all movies

have to be fit within that 16:9 shape. If a movie, like LOTRs, is wider than 16:9 then it must be shrunk in size so the width fits Blu-Ray's 16:9 shape. That leaves empty space above and below the image - giving you the infamous "black bars" of unused space for wider than 16:9 movies like star wars or LOTRS. Those black bars, though, are STILL part of the projected Blu-Ray 16:9 image, but that unused space is encoded

as black, so that that part of the image appears as black bars.

So, with the Blu-Ray's set of pixels ALWAYS making for a 16:9 projected shape, if you watch 16:9 shaped movie like 2 Broke Girls then the entire 16:9 image is filled. If you watch LOTRs, then part of that 16:9 image is made into black bars above and below the shrunken LOTRs image.

So if you are projecting a 2:40:1 movie like LOTRs on your 2;40:1 shaped screen, if you are using the "zoom method" you will have zoomed those unused black bars off your screen, when fitting the movie to your screen. But if you put on 2 Broke Girls, that movie's image is a taller one on Blu-Ray, taking up the "black bar" area that was unused in LOTRs. So now you'd notice that what were once invisible black bars outside your 2;40:1 acreen (with LOTR) they are being used for the taller

image of 2 Broke Girls, hence you have portions of that movie spilling off your screen top and bottom. To see the whole image contained on your 2:40:1 screen you have to re-zoom the image down in size, to get it's height to fit within your 2:40:1

screen. This now leaves you with unused space on the side of your 2;35:1 screen.

The usual way around this is employing an anamorphic lens. But since you are first trying to grasp the zoom method, I won't go further than that.

Archaea

stanger89

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
Quote:
Originally Posted by WestbrookUSA  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24351499

Hypothetical case:

I have a 2.4 screen and with my 16:9 projector I zoom the image to fit the height. I watch 2 Broke Girls and everybody's happy. Nobody cares about the vertical side black bars.

Then, Daddy puts in Lord of The Rings in 2.4 and blammo the image fills the entire 2.4 screen and I didn't zoom anything.

Is the hypothetical case a correct understanding?

No, in addition to what Rich said, since your projector is 16:9, and you zoomed it to fill the height of a 2.40:1 screen, the image coming out of the projector does not fill the screen. There are only two ways to make a 16:9 projector fill a 2.40:1 screen, zoom so that it fills the width (which will result in 33% of the 16:9 image falling above and below the 2.40:1 screen), or using an anamorphic lens to change the shape of the projector's output to 2.40:1, thus filling the screen without overspill.

WestbrookUSA

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R Harkness, thank you very much for breaking it down so neatly.  You explained it very well. (/aside I wish there were stickies in these forums because even though I searched and searched before posting, it still took a kind soul out there to break things down to the most basic particles for it to register /aside)

What a pain in the neck!  Seems crazy they don't have projectors which just shoot at the AR of the source and instead rely on the user to modulate settings or employ expensive solutions.

I was actually hoping to run CIH because I strongly favor the idea of big movies and smaller tv shows.  I definitely don't want to muck around with the manual zoom on the Sony 55es each time i'm going between formats and the A lenses are damn expensive from what i've gleaned.

I guess I'm just gonna have to live with black bars top and bottom.  Which will still be awesome, only it will seem strange shrinking the movies down to a size smaller than tv.

R Harkness

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Have you already bought the Sony?

Powered zoom/focus and lens memories, which will re-zoom an image for a 2:40:1 screen at the touch of a button, are becoming common features in protectors. Most of the JVC's have it, Panasonic, I'm not sure of the full list.

WestbrookUSA

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I do already possess the Sony 55es but I haven't opened it yet, in fact it hasn't been delivered because I work for a living therefore I'm not at home to sign for it..

I purchased it from amazon when I didn't understand all these interesting gotcha's.

My room is short on width so the manual zoom might force me into a situation.  I will fiddle with the calculators and report my findings.

Re: the projector, I have good light control, 12-13' throw, 79" ceiling, good WAF.  65/35 movies/tv&games.  Will fiddle with the calcs and report back.

Thanks again for the input everybody!

Josh Z

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This is what it looks like when you project a 16:9 image into the center of a 2.35:1 screen at minimum zoom:

This is what it looks like when you put in a letterboxed 2.35:1 movie without touching any of your settings:

This is what it looks like when you zoom the 2.35:1 image to fill the 2.35:1 screen. The black letterbox bars at the top and bottom spill off the screen onto your walls:

This is what it looks like when you put in 16:9 content again without reducing the zoom back to the original setting:

Read more in this Constant Image Height Tutorial .

Josh Z

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If you're annoyed with having to zoom in and out, you could leave the projector at maximum zoom all the time and use a video processor (such as a Lumagen Radiance 3D-Mini) to electronically shrink the size of the 16:9 picture and windowbox it in the middle of the screen with black bars on all four sides. The bars at the top and bottom will continue to spill off the screen and your image will fill the height of the screen similar to example #1 above.

However, doing so, you throw away a lot of resolution and picture detail (reducing the image from 1920x1080 to 1440x810), and your picture will be dimmer than minimum zoom because you're needlessly spreading the light over a larger area.

John Schuermann

R Harkness

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Quote:
Originally Posted by Josh Z  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24352887

If you're annoyed with having to zoom in and out, you could leave the projector at maximum zoom all the time and use a video processor (such as a Lumagen Radiance 3D-Mini) to electronically shrink the size of the 16:9 picture and windowbox it in the middle of the screen with black bars on all four sides. The bars at the top and bottom will continue to spill off the screen and your image will fill the height of the screen similar to example #1 above.

However, doing so, you throw away a lot of resolution and picture detail (reducing the image from 1920x1080 to 1440x810), and your picture will be dimmer than minimum zoom because you're needlessly spreading the light over a larger area.

I was going to mention that option too, but I figured if he'd had (or wanted to spend) the additional money for a lumagen product he could have just bought a projector with lens memories instead. (Not to mention adding a Lumagen

is not for the faint of heart for newbies anyway)

srauly

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If you're willing to throw away some detail, but don't want to spend Lumagen money, I think the DVDO Edge Green can support this feature as well. Looks like you can get one of those for under \$400.

Josh Z

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Quote:
Originally Posted by srauly  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24572214

If you're willing to throw away some detail, but don't want to spend Lumagen money, I think the DVDO Edge Green can support this feature as well. Looks like you can get one of those for under \$400.

Unless they've overhauled their software (I haven't checked them in a while), DVDO's aspect ratio controls are extremely rudimentary and limited compared to Lumagen.

RJW1966

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Quote:
Originally Posted by R Harkness  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom/0_100#post_24352082

Have you already bought the Sony?

Powered zoom/focus and lens memories, which will re-zoom an image for a 2:40:1 screen at the touch of a button, are becoming common features in protectors. Most of the JVC's have it, Panasonic, I'm not sure of the full list.
So, some of the JVC projectors will adjust for the AR with out the need of the anamoroph lens or zooming and loosing the picture to black bars? I am asking because I am interested in updayhing my projector soon and I dont want to mess with the lens or waste resolution on black bars. I want the projector to just do this for me as well.

Josh Z

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Quote:
Originally Posted by RJW1966  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24601998

So, some of the JVC projectors will adjust for the AR with out the need of the anamoroph lens or zooming and loosing the picture to black bars? I am asking because I am interested in updayhing my projector soon and I dont want to mess with the lens or waste resolution on black bars. I want the projector to just do this for me as well.

No. The projector shines a 16:9 image. You will either have to zoom (letting the letterbox bars spill off the top and bottom of your screen) or add an anamorphic lens plus scaling. Read through this thread again and some of the articles that were linked earlier.

rcohen

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If you use a HTPC, some of the player software has nice scaling options, so no need for a processor. JRiver, for example.

Still, you lose brightness and resolution, compared to zooming.

John Schuermann

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Quote:
Originally Posted by WestbrookUSA  /t/1517551/going-from-2-35-to-1-78-and-back-again-why-must-i-zoom#post_24352403

I do already possess the Sony 55es but I haven't opened it yet, in fact it hasn't been delivered because I work for a living therefore I'm not at home to sign for it..

I purchased it from amazon when I didn't understand all these interesting gotcha's.

My room is short on width so the manual zoom might force me into a situation.  I will fiddle with the calculators and report my findings.

Re: the projector, I have good light control, 12-13' throw, 79" ceiling, good WAF.  65/35 movies/tv&games.  Will fiddle with the calcs and report back.

Thanks again for the input everybody!

Curious what you ended up with. The Sony does have the scaling necessary if you ended up going the lens route. What size screen did you get?

Potatogod93

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This question is a little premature and I need to try the projector to wall trick before buying a screen. In my head, though, I have an idea of what I want to do. CIH with a 141" scope screen which would give me about a 112" inch screen for 16:9. But when zoomed for 2.35:1 It'd be like having 149" inch 16:9 screen so I'd be shooting close to 9 inches above and below the screen.

With only about 7.5 feet before ceiling starts with this hypothical setup I'd be shooting some black on the center channel and the ceiling. Now my celing is planned to be flat black, but my question is would this look stupid? I mean I will test this as my room gets completed but I like to have a plan to go by and think about. Thanks!

Josh Z

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With only about 7.5 feet before ceiling starts with this hypothical setup I'd be shooting some black on the center channel and the ceiling. Now my celing is planned to be flat black, but my question is would this look stupid? I mean I will test this as my room gets completed but I like to have a plan to go by and think about. Thanks!
You should be fine. Projecting some black onto it won't hurt the speaker.

Unless the speaker is a reflective metallic color, you will most likely not notice the light projected onto it.

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