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#### JapanDave

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I read the FAQ and searched the forum and I still can't get my head around why CIH is better (Has more resolution).

Lets say your room limitations are its width, so you can only have a 120" wide screen. Wouldn't the image from the projector essentially be same size height and width wise on a 16:9 screen (not taking the black bars into account) even when using an anamorphiclens lens on a 2.37:1 screen of 120" in width? If that is the case , then what is the advantage of using an anamorphic lens? B/c you will get better resolution, now this is the part I can't wrap my head around. Any help would be apreciated for a noob.

#### JapanDave

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I think I have got it, the black bars have to be taken into account when measuring the resolution, so when you stretch the image height wise you are using the whole of the projetors potential and the anamorphic lens stretches the image width wise so you are then using the projetors full resolution. If I have this wrong please let me know, cheers.

#### Aussie Bob

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Resolution

Pixel resolution of zoomed systems

When you zoom an image out by 1.33x to fit a 2.35 screen you increase the size of the pixels both vertically and horizontally by one-third (4/3). This equates to a comparative resolution (between zoomed and original sized picture) of the square of the inverse of 4/3 ... 3/4 squared = 9/16 = 56%... or 44% pixel resolution loss at a fixed viewing distance.

Pixel resolution of anamorphic systems

When you use an anamorphic lens to optically stretch an image in only the horizontal direction, the vertical pixel size remains the same as before, with only the horizontal pixels increasing in size by one-third. This equates to 3/4 the resolution of the original non-anamorphosed picture, only a 25% reduction in resolution (compared to 44% with zooming).

Summary... with an anamorphic lens you only lose pixel resolution in one direction: horizontal. Overall, using a lens has the potential to give better pixel resolution than straight zooming, depending on the quality of the optics in the lens.

Picture resolution of zoomed versus anamorphic systems

But pixel resolution is not the only consideration. There is picture resolution to look at too. Picture resolution relates to the content of the image that is made up of individual projector pixels. Average picture resolution is usually lower than the projector's maximum pixel resolution. Think of a standard DVD projected out of a 1920x1080 projector: the limiting factor, as far as clarity and resolution of the final viewable image is concerned is the picture resolution of the DVD image (720x480 NTSC or 720x576 PAL), not the pixel resolution of the system (the 1920x1080 projector). Even Blu-Ray disks have very little (if any) full resolution detail in them. The pixel resolution, if higher than the picture resolution, may be wasted. Put another way, the total system is only as sharp as its softest component.

You will lose some picture resolution (as opposed to pixel resolution) via the digital vertical stretch (digital extrapolation) that you must use as part of the anamorphic lens process. How much this loss amounts to has been a subject of hot dispute here.

One recent study by Cine4Home showed that static test patterns - 1x1 pixel checkerboards, single-pixel vertical lines and so on - lost resolution due to the vertical stretch process. This is actually not a very startling revelation as a repeated 1x1 pixel pattern is the highest resolution a projection system can offer. There must always be some loss when that pattern is disturbed by stretching it, especially by a fractional value like 4/3. This resolution loss would also apply to video gaming and similar PC-based displays where single pixel resolution may be common, especially in fine text.

The question to ask is whether "real-life" viewing images with continuous tones and continuous detail (e.g. movies) have as much noticeable loss of resolution as their static counterparts?

As a first consideration, most of the detail in a movie is at a far lower resolution than a static 1x1 pixel test pattern. Much of it is continuous in nature (subtle shade and color shifts from dark to light areas, rather than hard-edged single-pixel fields of a test pattern). Movie detail is also moving detail. Our eyes find it harder to distinguish subtleties of detail when the macro contents of the image are moving about (once again as distinguished from the static detail of a test pattern). The human eye is much better at detecting changes in a static scene with high contrast changes over small areas (a test pattern) than it is with a moving scene with low contrast shifts across similarly small areas (a typical movie).

In my opinion, the Cine4Home test was a useful, yet technical, demonstration of the viability of extrapolation algorithms when used with static detail. As an indicator (as seemed to be claimed) of significant detail loss when using an anamorphic lens passing a vertically stretched image, it was less useful. The Cine4Home test was not comparing apples with apples. It did not take into account the factors mentioned above, which can be summarized as "movies are not test patterns".

Brightness

Because the image when an anamorphic lens is employed is only being widened and not made higher (hence "Constant Image Height") the loss of brightness is less than when the picture is enlarged in both directions. Anamorphically stretched pixels are 4/3 times the area of the original pixels. Zoomed pixels are 16/9 times (4/3-squared) the area of the original pixels. 16/9 divided by 4/3 gives a theoretical 33.3% brighter picture for anamorphically stretched images.

From this some transmission loss - the amount of light lost as the projection beam passes through the optics of the lens - needs to be subtracted. For an anti-reflection coated (AR) system, figure about 0.5% per surface, giving (roughly) something like 4% for a 4-element lens. Let's rule it off at 5% for luck.

So now your anamorphic system is only 28% brighter than your zoom system.

Next we need to subtract some more brightness (or actually add brightness to the zoom system, which amounts to the same thing) due to the greater efficiency of a zoom lens when it is zoomed out for a wider picture. Normally, doubling the dimensions of a projected picture would leave the enlarged picture 1/4 as bright as the original, but due to the optics of zoom lenses used for projection, this figure is closer to 1/3 as bright. Yes, there is still some loss, but it is not as much as you'd think merely from applying a straight area comparison between the sizes of the "before" and "after" screen images. So, our nominal 28% brightness dividend from using an anamorphic lens most likely comes down to around a working total of 10%-20% brighter, depending on the optics of the projector.

Conclusions

1. Overall, effective (i.e. noticeable) resolution loss with an anamorphic lens is not as much as has been claimed. There is a clear dividend optically, if good optics are used (color-aberration corrected, AR coated, quality glass, good design).

2. Whether this optical resolution dividend is cancelled out by the digital stretch process is arguable. In my personal view, it is not entirely cancelled out, due to the nature and resolution content of the image being viewed (especially if the images are movies). My opinion is that, given good optics, anamorphic systems have the potential to be sharper than zoom systems, and more "pleasing" to look at from closer distances (i.e. in small HTs) due to the smaller pixel area.

3. An anamorphic system is most likely from 10%-20% brighter than a zoomed system. Once again, good optics are a prerequisite.

4. All of the above depends on good optics and the individual projection system, comprising projector (of course!), room size, seating arrangements and so on.

5. There are other things to be considered too which were not discussed above. Some systems (particularly DLP) do not have the zoom and offsetting capabilities that are required for the Zoom Method. Or if they do, the room is too small. Some systems do not have vertical stretch. Pincushion distortion is another bug bear. If you don't like pincushion distortion, zoom (although pincushion is pretty small at TRs over 2.0). These considerations should all be weighed when deciding whether to use a lens or zooming.

Personal Observations

For the record, I use a cylindrical lens of my own design with a JVC HD-100 (RS2 in the US). I believe my optics are very good (pats self on back). It resolves a 1x1 pixel dot pattern cleanly all over the screen. It does not affect focus whether the lens is in or out of the beam.

There is quite a noticeable drop in brightness between the anamorphic lens setup and zooming. Switching between 16:9 and zoomed 2.35:1 pictures is a real pain with the JVC HD-100. You can't just zoom, re-offset the lens and re-focus. Refocus and zoom are strictly menu operations and you have to go to a fair amount of trouble to access these functions. This re-alignment of the system can take 2 minutes setting up and another 2 minutes restoring things to normal.

By contrast, if I want to switch between 16:9 and 2.35:1 anamorphically I just slide my lens out of the way in literally 2 seconds... no re-focus, no-re-zoom, no re-offsetting. Much, much quicker and more convenient.

And a better, brighter image, too.

(Room details: screen size 120" x 51", Throw Distance ~15 feet, Throw Ratio ~2.1)

#### JapanDave

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Thanks AussieBob, that does make things a lot easier to decide on whether it is worth it to go CIH.

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#### GG386

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One thing with AB's posts, you get that Aussie wit at no charge

#### Jason Turk

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
Quote:
Originally Posted by JapanDave /forum/post/16826264

I read the FAQ and searched the forum and I still can't get my head around why CIH is better (Has more resolution).

Lets say your room limitations are its width, so you can only have a 120" wide screen. Wouldn't the image from the projector essentially be same size height and width wise on a 16:9 screen (not taking the black bars into account) even when using an anamorphiclens lens on a 2.37:1 screen of 120" in width? If that is the case , then what is the advantage of using an anamorphic lens? B/c you will get better resolution, now this is the part I can't wrap my head around. Any help would be apreciated for a noob.

If you are limited by width, you are right it doesn't make a lot of sense. In a 120" wide image, weather you have a 67.5"x120" 16:9 or a 51"x120" 2.35:1 screen, the 2.35:1 image is the same. So it doesn't make a lot of sense to spend all the money on the 2.35:1 screen, lens, etc... That is unless all you watch is 2.35:1 stuff, in which case going 16:9 is useless.

Usually those who do 2.35:1 are going CIH where the 16:9 height is the same as the 2.35:1 height, the screen is just wider.

#### taffman

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Josh, thanks for the link to that excellent article, which I thought was very informative, and fair and unbiased about the pro's and con's of zooming versus lens.

As a zoomer, the biggest objection I have towards lens users is their constant claim that the A-lens actually improves picture quality over zooming.

There is no clear evidence to support this ( except for a 15% improvement in brightness), in fact several posters on this forum have had the opposite experience and have gone from A-lenses back to zooming because they get a sharper picture. Aussie Bob has eloquently (as usual) pointed out that the PQ is limited by the source material not the projection method.

I agree that the A-lens is elegant and less hassle for many people (except Panasonic AE3000 users, who have it made with automated zoomed CIH), but claims of superior PQ are surely very questionable. So much so, that it would take a real act of courage for me to spend \$11,000 on an Isco lens without any means of seeing it or testing it before hand!

Bottom line is that CIH can be stunning using the zooming method, so you do not need to spend a fortune to get awesome 2.35. To me the risks of investing \$11,000+ sight unseen for a top quality A-lens, for what may only be at best a marginal improvement in PQ in my particular set up, is just unnacceptable.

#### Aussie Bob

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Quote:
Aussie Bob has eloquently (as usual) pointed out that the PQ is limited by the source material not the projection method.

anamorphic lenses also add some brightness, plus convenience. There's a smoother look too, but this is dependent upon viewing distance. I like to sit close up to the screen (so close I have to turn my head from one side to the other). It makes viewing movies more realistic. Additionally, in my case it's an awful lot more convenient to just slide the lens away and back in again depending on format.

I didn't know Iscos were now US\$11,000. That's outrageous!

#### thebland

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Quote:
Originally Posted by Aussie Bob /forum/post/16831296

I didn't know Iscos were now US\$11,000. That's outrageous!

Are you kidding... I paid less than 1/2 that 2 years ago!!

I think the info is wrong.. Last I heard, close to \$7000

#### GetGray

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\$11k. I wish
. Except no one would by one. The \$7k range is MSRP. Local dealer or Jason here at AVS would be a good place to determine going rates.

#### Vern Dias

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Quote:
except Panasonic AE3000 users, who have it made with automated zoomed CIH

I know that the AE3000 is a very popular projector for those zooming, but I would be remiss in not pointing out to those considering this projector, that there is no way you will actually see the full image detail made possible by BD discs on this projector when sitting at a viewing distance that allows your eyes to fully resolve a 1080 image, regardless of your choice of lens vs zoom.

The Smoothscreen technology used in these projectors result in a softer less detailed image than you would see from most DLP or LCOS (DILA / SXRD) based projectors (unless it has a really crappy lens). While Smoothscreen certainly helps to hide the screen door effect often seen with that technology and made worse by a zooming solution, it also hurts the image detail using either zooming or an anamorphic lens.

An real world example:

Way back when Patton was released on BD, some of us with larger screens could not believe how much DNR was applied during the transfer. Basically it totally obliterated any fine skin detail.

And yet, there were those who said it wasn't nearly as bad compared to other titles as what some of us were seeing. Eventually, I had the opportunity to do an AB comparison of Patton with other BD's in a differnt HT and I initially had to agree that it wasn't as bad as I remembered in comparison to other BD's.

But, as the viewing went on, I realized that all the BD titles we watched were missing the really fine detail that a good BD transfer is capable of. At first I thought it was a focus issue, but refocusing didn't improve the situation.

Then I realized, it was the projector!! It was a Panasonic AE3000 and the culprit was clearly the Smoothscreen processing applied to help hide the (relatively) large inter pixel gaps inherent to the technology.

So, when you hear people on the board comparing zooming vs lens, remember that many other factors, including projector tecnology, both prime and anamorphic lens quality, room size and shape, screen size, visual acuity, personal goals, and viewing distance all factor into making the correct choice for optimum results in the 2.35 CIH world.

Vern

#### taffman

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Quote:
Originally Posted by Vern Dias /forum/post/16833689

The Smoothscreen technology used in these projectors result in a softer less detailed image than you would see from most DLP or LCOS (DILA / SXRD) based projectors (unless it has a really crappy lens).

Vern

This is a ridiculous statement, implying that the Panasonic is only as good as a DLP projector that "has a really crappy lens'. I happen to own a Panasonic and I know good picture quality when I see it, and believe me the picture is very sharp and detailed indeed - not the least bit soft. Projector Central also came to the same conclusion, when they ran side-by-side tests of the Panny against a Sanyo, and found zero difference in sharpness after adjusting sharpness level on the Panny. ( One variable here is the sharpness setting on the projector, which can make a huge difference, and the default sharpness setting on the Panny's may be softer than those on other projectors.)

Vern's distaste for and constant bashing of Panasonic SST is well known, but making ridiculous statements about " only as good as a DLP projector with a crappy lens" makes his case lose all credibility.

I think SST is a wonderful technology, resulting in really film-like images, and as a film projectionist I do know what I am talking about.

#### Jason Turk

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Could he have meant \$11k AUSTRALIAN? Not sure, but as GetGray said the MSRP is \$7kish.

#### Josh Z

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Quote:
Originally Posted by taffman /forum/post/16834196

( One variable here is the sharpness setting on the projector, which can make a huge difference, and the default sharpness setting on the Panny's may be softer than those on other projectors.)

Don't confuse electronic sharpness filtering for real optical sharpness. They're not even remotely the same thing.

I have no opinion on the Panasonic projectors, but that comment really struck me as being off-base.

#### Jason Turk

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Good call Josh...electronic sharpness is really edge enhancement...optical focus is the ability of the lens to accurate enlarge and reproduce what is coming off the chip (regardless of technology).

#### Vern Dias

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Quote:
and as a film projectionist I do know what I am talking about.

Well, as one projectionist to another.... I have been a projectionist for around 40 years now and have a pair of 35mm projectors in my HT. And yes, the Panasonic is soft and definitely suppresses the fine details such as skin textures and film grain. My comparisons are based on a Sony Qualia 004 where the lens alone cost more than some projectors. However, the newer JVC's and many DLP's also deliver an image with loads of detail for considerably less \$ than the Qualia.

BTW, I never said the projector is as good as.... I did say that the image detail is as good as..... Exact words: "softer less detailed image...." Big difference there!

And BTW Sharpness != Detail in the video world. With film, sharpness and detail are directly related. With video, you can have an apparently sharp image that carries little or no fine detail. So please don't confuse the two, or assume that I am am saying the Panny is not a good projector in many respects (other than not delivering all of the detail present on high quality HD sources to the screen).

Vern

#### Gary Lightfoot

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Quote:
Originally Posted by taffman /forum/post/16829824

As a zoomer, the biggest objection I have towards lens users is their constant claim that the A-lens actually improves picture quality over zooming.

There is no clear evidence to support this ( except for a 15% improvement in brightness),

When zooming, it's like you're moving your seating closer, so the pixels become bigger and more visible and the image comparatively more blocky. With an A lens this doesn't happen since the vertical res is increase by interpolation, so the pixels don't get any taller. The lens is effectively only zooming in the horizontal where our vision is less sensitive so any artefacts pixels or screendoor aren't exacerbated in the same way as with zooming, and you can also sit closer to your screen.

When I compared zooming to an A lens in my own HT with my 720 DLP pj a few years ago I could see the potential - my initial lens was a cheap loaner that I had for a few weeks but I wasn't completely convinced, though I could see the potential benefits. My next lens was much better quality (ar coatings and no ca) and bought new with a 14 day return period. The improvement was obvious so I never returned it (if zooming was better why did I not get my money back which I easily could have done?).

I was able to buy a second hand ISCO II later on and did a direct comparison to the prism based lens I was using at the time. The ISCO was better still so I sold the prism lens (again, if zooming was better why did I buy a second lens?). I can concur with Aussie bob that with video patterns the difference was perceptible, but with video far less so.

I had also seen a Sony HS50 in my HT zooming to 2.35 on my screen and even though we were sitting at around 1.5 x the screen width at the time SD material looked noticeably blocky there too. That of course was with 720 displays and mostly SD material, so perhaps the advantage of a lens with 1080 is less, but when you see how many people have compared their 1080 images with zooming and a decent A lens most appear to have gone with the lens option.

If zooming was better with my pj I certainly wouldn't have bought two A lenses.

Quote:
Originally Posted by taffman /forum/post/16829824

in fact several posters on this forum have had the opposite experience and have gone from A-lenses back to zooming because they get a sharper picture.

That's probably because they were using a cheaper lens or felt the cost was greater than the benefit they saw. More people have gone from zooming to using a lens and stayed there.

But each to their own. All that counts is that people are happy with their choices. I think 2.35 is the way forward and anyone who goes that route either via zooming or a lens is improving their home theater experience - otherwise they wouldn't be doing it. Strangely enough there are some out there who argue that 16:9 is the best system with black bars top and bottom and scope is a poor quality option however you do it. I'm sure you'll agree that if it was as bad as they say you wouldn't be zooming (and others wouldn't be using a lens).

It's a similar argument - if all lenses were bad, people wouldn't buy them, and if 2.35 was bad, people would remain at 16:9. It's not the case in either scenario of course because people have opted for them over the other choices.

Gary

#### 5mark

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Quote:
Originally Posted by Vern Dias /forum/post/16833689

So, when you hear people on the board comparing zooming vs lens, remember that many other factors, including projector tecnology, both prime and anamorphic lens quality, room size and shape, screen size, visual acuity, personal goals, and viewing distance all factor into making the correct choice for optimum results in the 2.35 CIH world.

Well said. It would be nice if people used less generalizations such as, "Using a lens is a necessity", or "Using a lens is not worth the money". Either statement could be true in one situation but not across the board.

For ex, if you have a high end DLP projector with an ultra sharp lens viewed on a huge screen, adding a top quality lens seems like a no-brainer (think Art's setup) However, a projector with smoothscreen really wouldn't benefit much from a lens (even a high end one) and would become mostly about convenience.

From what I've seen, LCOS technology achieves a nice compromise between sharpness, detail, and a filmlike image that can be viewed from a short distance. Using a lens or not becomes a tougher decision. In my short throw setup, zooming made the most sense. After adding a VP and the shrink method it feels like the best of both worlds (PQ and convenience). In fact, I think everyone should use the shrink method. (Just kidding of course!!!!)

#### Kelvin1965S

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Quote:
Originally Posted by 5mark /forum/post/16836428

In fact, I think everyone should use the shrink method. (Just kidding of course!!!!)

I thought everybody did.....or is it just us two?
I'll carry on using this method until such time as I find a quality used lens to try (so that I won't take to much of a hit if I find it's not for me).

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