Behind the Mask: Aspect Ratio Solutions for Projectors and Screens (2 Viewers)

[ManW_TheUncool]

OK - maybe I'm getting it. You're basically saying the anamorphic lens will make the image displayed by the Epson's Anamorphic setting look natural while still filling my 16x9 screen?

Actually, after "unsqueezing", it'll look natural at 2.35:1, not fill your 16x9 screen -- it's meant to fill a 2.35:1 screen while not wasting light output (that would otherwise be lost to the letterbox black bars).

Exactly, and why is that? Is it because they aren't sold in sufficient quantity to drive the price down?

I would think that's probably the biggest factor re: anamorphic lenses.

However, with the advent of HDR and (renewed) usefulness of max light output (that FP general lacks), I wonder if that might change somewhat as people start realizing the advantage of regaining the light output that's otherwise lost to the letterbox bars (in addition to not having visibly gray bars). Probably not much, if any, since the FP market will likely always be small (and the higher end, where such features reside, that much smaller)...

_Man_

 

[John Dirk]

Actually, after "unsqueezing", it'll look natural at 2.35:1, not fill your 16x9 screen -- it's meant to fill a 2.35:1 screen while not wasting light output (that would otherwise be lost to the letterbox black bars).

I would think that's probably the biggest factor re: anamorphic lenses.

However, with the advent of HDR and (renewed) usefulness of max light output (that FP general lacks), I wonder if that might change somewhat as people start realizing the advantage of regaining the light output that's otherwise lost to the letterbox bars (in addition to not having visibly gray bars). Probably not much, if any, since the FP market will likely always be small (and the higher end, where such features reside, that much smaller)...

_Man_

Great explanation. Thank you. Personally, I also have to agree with @Sam Posten on this one. My 16x9 screen is a "compromise" I'm happy to make, all things considered. As stated in a previous thread, I've given up on the notion of worthwhile HDR from a projector, at least in my price range.

 

[John Dirk]

In the end, you’re getting the same visual information, but you’ve just spent thousands of dollars on a lens attachment so that the black bars on a 2.40:1 image are cropped our before projection rather than during projection.

Thanks Josh - I'm starting to understand why sales of anamorphic lenses are likely so low.

 

[Mark-P]

Now that I finally have such an equipped FP (ie. Epson 5050UB) and planning a dedicated HT room, I might finally go w/ a 2.35:1 screen.

Thing is that doesn't work so well for IMAX format movies though. And not sure what to do w/ the rare ultrawide ones like Ben Hur and Hateful Eight -- I suppose that's rare enough to just accept the smaller (still) letterbox image. But seems like there may be more and more IMAX format movies that deserve a bigger presentation (whether they involve changing AR or not).

My first attempt at a do-it-yourself 2.35:1 had that very issue. 70mm and IMAX movies were smaller and they shouldn’t be. My next attempt was a 2:1 screen with a bottom black mask attachment that mostly stays in place so that all movies from 1.19:1 to 2.35:1 have the same height and side curtains hide unused portions of the screen. Now the exception is for large format movies I lower the bottom mask so that the ratio becomes 2.2:1 for 70mm productions and for IMAX with a ratio of 1.9:1 I drop the mask all together. That bottom mask can also be raised to obscure black bars from ultra-wide 2.55:1 and 2.76:1 movies. Sam probably thinks I’m a complete nut job, but my do-it-yourself setup makes me completely happy.

 

[Sam Posten]

I've given up on the notion of worthwhile HDR from a projector, at least in my price range.

Its actually worse than that for me. I find myself not wanting to watch on my very expensive projector theater because it doesn't measure up to the significantly superior OLED panels and HDR.

 

[Josh Steinberg]

That’s what I had in mind if I can ever get a dedicated room for my projector - I haven’t had a space where I could get away with that yet. The key for me is that it’ll all be DIY, “don’t let the perfect be the enemy of the good” type of thing. But that’s exactly the concept I’m going for. I want to differentiate between 1.85:1 from 35mm and 1.90:1 from IMAX.

 

[Martin Dew]

I agree with a lot of the points about sticking to a 16:9 screen and I know many people who do this. I just personally prefer the wow factor of zooming the image to 2.35:1 and retaining some of the old magic of the theater.

I believe that anamorphic lenses in the home are pretty much redundant, particularly now that the vertical pixel count is roughly 1,600 on a 4K title; 800 pixels on 1080p projectors was a bit of a compromise.

 

[Peter Apruzzese]

Interesting. Would you mind posting a picture?

I’ll give it a shot, the problem is that it’s all black (curtain rod, rings, etc) and might not show up clearly.

 

[John Dirk]

Thanks to everyone who jumped in to help me better understand this topic. I'm using this particular post to continue the discussion only because it addresses all of my remaining areas of confusion.

Basically, when you use an anamorphic lens, you do two things. The first is you have your disc player or another image processor take a letterboxed 16x9 image and crop out the black bars that are normally used to fit a 2.40:1 movie into a 16x9 format. Now you have a frame that’s wider than 16x9 but without the black bars in the frame. This is then squeezed back into a 16x9 frame.

So in my case the image processor referred to is my Epson 6050, right? When I select the Anamorphic setting it vertically stretches the image, thus eliminating the letterboxing. When you say the resulting image is "wider" than 16x9, do you mean it is vertically taller?

I don't understand what you mean when you say the image is "then squeezed back into a 16x9 frame."

Then, the lens on the projector unsqueezes that image during projection back to a wider than 16x9 frame.

Again, unless you mean the anamorphic lens vertically shrinks [squeezes] the image back into it's original 2.40:1 frame then I remain confused on this point.

Or, you do as most people do with 2.40:1 screens, and just adjust the zoom/lens memory on the projector.

Wouldn't this result in loss of vertical picture data?


Here is the identical scene from the Star Trek IV 2.35:1 Blu Ray using the Normal and Anamorphic settings.
In Normal mode there are black bars above and below the image as expected. The progress bar is visible at the bottom.

In Anamorphic mode, as far as I can tell, the projector performs an electronic vertical stretch to utilize the entire 16x9 screen, thus removing the black bars. The progress bar is not visible onscreen. It does not appear to do anything more as the horizontal boundaries remain the same. The added light in this shot is due to me slightly advancing the frame. Since I don't have the anamorphic lens to complete the process, I don't expect a perfect image, yet the resulting image is watchable, albeit a bit unnatural. If I did have the anamorphic lens, my understanding at this point is it would return the image to it's original letterboxed appearance but the projector would be unaware of this and still use all of it's available brightness to fill the screen, with the anamorphic lens concentrating that light into a 2.35:1 frame. Now the black bars would exist because no light is being projected into those areas.

Please help me understand what I am missing as I'm pretty sure I still don't have this quite right.

Again. All explanations are much appreciated. This is one of those topics I would like to nail once and for all although I already know I'll never actually purchase an anamorphic lens.

 

[JohnRice]

I don't understand what you mean when you say the image is "then squeezed back into a 16x9 frame."


Again, unless you mean the anamorphic lens vertically shrinks [squeezes] the image back into it's original 2.40:1 frame then I remain confused on this point.

The anamorphic processing of the projector stretches the image vertically so the 2.35x1 image is now 1.78x1. Then the lens technically stretches the image horizontally an equal amount to get it back to 2.35. The goal is to end up with an image that's the same height as a 1.78 one, but is wider, resulting in 2.35. That's the entire concept of "constant image height"

It made more sense with film, since it resulted in a higher resolution image. That's not the case here, though it results in a brighter image.

 

[Josh Steinberg]

@JohnRice said it more concisely than I could

 

[John Dirk]

Actually, after "unsqueezing", it'll look natural at 2.35:1, not fill your 16x9 screen -- it's meant to fill a 2.35:1 screen while not wasting light output (that would otherwise be lost to the letterbox black bars).

The goal is to end up with an image that's the same height as a 1.78 one, but is wider, resulting in 2.35. That's the entire concept of "constant image height"

Not to put anyone on the spot but how can both of these statements be true. I feel like I'm so close to getting this.

 

[JohnRice]

Man and I might be talking about different approaches. I‘m referring to CIH, and Man appears to not be.

 

[John Dirk]

@JohnRice said it more concisely than I could

Thanks for taking the time to say it at all.

 

[Dave Upton]

Not to put anyone on the spot but how can both of these statements be true. I feel like I'm so close to getting this.

Think of it this way: without the squeezing of the image in your player or video processor a lot of your projectors pixels are wasted on black bars. These black bars are ultimately going to reduce the amount of light that reaches the screen. When you use an anamorphic lens, you eliminate the black bars in the player or video processor, so that the projectors LCD panel is only projecting light not black bars. If you were to put that image on the screen without an anamorphic lens, it would look very funny and squeezed.

All the anamorphic lens does is take that squeezed image and fix its aspect ratio back to a normal 2.35 to 1 ratio. On a 16:9 screen, you would still see black bars, but they aren't from your projector, Just unfilled space that the image does not contain information for. And most high-end home theaters that use anamorphic lenses, the masking system slides to the left and right making the screen wider overall but maintaining the same height, the amorphic lens then fills this wider image using more of the projector's light output giving a brighter image than would be achieved with just zoom

 

[John Dirk]

Thanks guys. I think I get it now. This topic is much easier to understand from the perspective of a 2.35:1 screen, which I don't have. I'm a visual learner and this helped tie it all together for me.

A Constant Image Height Refresher

If projector owners are a niche within the home theater hobby, Constant Image Height projection users are a niche within a niche. A lot of that comes ...

www.highdefdigest.com

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[JohnRice]

OK, the vocabulary nit-picker comes out in me. Words seem to be interchanged a lot these days, and I think it's the source of some of the confusion here. "Stretch" and "Squeeze" are not interchangeable. They have basically opposite meanings. So, to me, you can't "squeeze" an image to make it larger. Just like you can't "Stretch" one to make it smaller. So, the anamorphic setting on a projector has to stretch the image vertically to make a 2.35 image fill the 1.78 space. Then, the anamorphic lens has to stretch it horizontally to bring it back to 2.35. The combined stretch functions result in an image with larger total area and the same aspect ratio it started with. Using the word "Squeeze" to describe any of this will probably cause confusion. Sorry, along with Photography, I was also an English Lit major.

 

[Mark-P]

The anamorphic lens (for projectors at least) really has become obsolete. Lens functionality has become so good with the ability to zoom, shift in all directions and then memorize those positions that it functionally works better than an anamorphic lens, and projectors have enough brightness these days that you really don’t need the entire pixel grid for a completely acceptable 2.35:1 image. Anyone is of course free to disagree.

 

[John Dirk]

The anamorphic lens (for projectors at least) really has become obsolete. Lens functionality has become so good with the ability to zoom, shift in all directions and then memorize those positions that it functionally works better than an anamorphic lens, and projectors have enough brightness these days that you really don’t need the entire pixel grid for a completely acceptable 2.35:1 image.

This is the conclusion I've come to as well, especially when the screen in question is 16x9. Nonetheless, this thread has been a wonderful education on the topic for me and I want to thank all of the experts who chimed in to distill it down to my level.

 

[Indy Guy]

Sorry for coming late to the party, but I fretted over this issue 4 years ago when I was planning my 4K/3D upgrade. The solution presented itself in a projector that is, to this day unique in its ability to handle all aspect ratios in the best possible way. Barco Balder Cinemascope.
Barco made a deal with Texas Instruments to produce a DLP 5K+ scope shaped chip. The scope shaped chip delivers 4K 16x9 material to the 16x9 central portion of the chip, but when the projector detects wider content...1.85 on up, it used the unique wide pixel array to carry the added scope content. This results in not only a brighter images, but more pixels actually projecting the image! The quality improvement can be dramatized by thinking of a photo with a fixed resolution appearing in a newspaper vs a magazine. The resolution enhancement is not from the original photo, but the dots of resolution in the printing process.
The Barco has some quirks in the auto detect feature for aspect settings especially when viewing commercial TV, but it can be defeated and switched to manual when you start to get vertigo from the rapid varying aspects of ads and content.
The Barco is also expensive, but outperforms and eliminates the need of an anamorphic lens by actually adding more pixels as needed rather than manipulating a fixed 16x9 chip. With the various aspect ratios produced by the size of the chip itself, DLP is a necessity. Other chip sets technologies would develop burn in using various aspect settings. DLP has zero burn in issues. The bottom line is, all imagery is constant height/constant vertical resolution. The wider the image, the more horizontal pixels are displayed to provide ever increasing quality to the more impressive scope formats.