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Why CIH??--Why not CIW?? - Page 2

post #31 of 114
Quote:
Originally Posted by Bigus View Post

Re: visual field of view and the various AR's...

The chart posted is our "all at once" field of view. The boundaries define our peripheral field of view... objects at those extremes are perceptible but without detail. We pick up motion and light here, not so much color or resolution of detail.

And yes, that field of view matches a 4:3 AR screen well. Ever wonder why that AR was chosen so many years ago?

So why then was there ever a move away from 4:3 towards wider AR's, and why do many find them more immersive than the "best fit" 4:3 screen?

Because we don't view the world by staring at a single fixed point. We scan our eyes... all the time. And we tend to scan horizontally (probably because the horizon happens to be horizontal, and thus we evolved horizontal binocular vision, not vertical binocular vision). Scanning horizontally is much more comfortable for us than scanning vertically. Another poster mentioned the recommended and maximum vertical angles for comfortable viewing... this isn't based on fitting the picture into our peripheral vision but rather the biggest size that we can take in that minimizes both our need to scan vertically as well as the angle we need to scan when we do.

So we scan not only to fit the entire picture within our peripheral vision, but also to discern detail in more peripheral areas of the screen. And this is why 4:3 isn't "as good" as wider AR's for the best experience. Just what the "best" AR is isn't quite as easy to determine as simple knowing that "wider than our field of view" AR is better. And thus decades of debates over and use of multiple AR's in both cinema and home.

And why does IMAX go back the other direction towards our field of view? I'm not really sure. So long as you sit really close, it certainly gives the screen shape that fills our field of view and thus the biggest "wow" factor when you first sit down. It may be tiring, but then how often do we watch IMAX movies? I don't see that AR at the seating distance used in an IMAX theater ever being acceptable for long periods of home viewing.

That leaves us then with the tired argument of which widescreen AR is the best. Who knows? I personally tend to think 2.35:1 is more impressive than 16:9 when (and this is important) the 16:9 image is at the limit of vertical height for comfort. I'm not sure of the purpose of posting a bizarre CIW Avatar example... who would mask down the screen in a CIW setup from 16:9 to 2.35:1 and then display a letterboxed 16:9 image??? The big 16:9 image is what you would see in home with a CIH setup. Any taller than that would be uncomfortable. You then have extra screen space to the sides to expand the horizontal FOV to 2.35:1.

Very helpful and informative post. So if I could summarize (and I realize this may be oversimplifying), if one wanted to build the ultimate immersive experience, the plan would be as follows:

1. Identify primary seating distance.
2. Identify maximum height of screen for distance in Step 1 that would not need vertical scanning. This in essence would be the biggest 16:9 ratio screen that one would want (any larger and it would require vertical scanning which would not be comfortable).
3. Based on the height from Step 2, have a 2.35:1 screen based on that height.


In summary, if cost is no object, then CIH should get the most immersive experience if you follow the steps above. Otherwise, if the width of the room or the light output of the projector don't allow as big of a CIH as you can handle (ie. without vertical scanning), then consider CIA to get the most immersive experience for both 2:35.1 and 16:9 viewing (otherwise the height for 16:9 viewing will be less than the maximum impact identified in Step 2).
post #32 of 114
Thread Starter 
Quote:
Originally Posted by Bigus View Post

And yes, that field of view matches a 4:3 AR screen well. Ever wonder why that AR was chosen so many years ago?

While I agree with your other viewpoints, I understand the reason we went with 4:3 was because some guy made a square shaped using his forefinger and thumb on either hand, turning them opposite each other and said, "I want it to look like that!" in regards to the first film projection system.
post #33 of 114
Thread Starter 
In regards to the discussion regarding vertical scanning and whether or not that's a bad thing, I agree that our eyes are more apt and able to scan horizontally, and vertical scanning may induce fatigue or what have you, but just because a screen is filling up our entire vertical range of vision, it does not mean we need to visually scan the whole image to take it in.
post #34 of 114
Quote:
Originally Posted by sipester View Post


1. Identify primary seating distance.
2. Identify maximum height of screen for distance in Step 1 that would not need vertical scanning. This in essence would be the biggest 16:9 ratio screen that one would want (any larger and it would require vertical scanning which would not be comfortable).
3. Based on the height from Step 2, have a 2.35:1 screen based on that height.

That's pretty much the plan.
post #35 of 114
Quote:
Originally Posted by javanpohl View Post

While I agree with your other viewpoints, I understand the reason we went with 4:3 was because some guy made a square shaped using his forefinger and thumb on either hand, turning them opposite each other and said, "I want it to look like that!" in regards to the first film projection system.

"Some guy" must have had some odd lengthed fingers then! When I do that the result is more like 16:9, maybe even wider.
post #36 of 114
Quote:
Originally Posted by javanpohl View Post

In regards to the discussion regarding vertical scanning and whether or not that's a bad thing, I agree that our eyes are more apt and able to scan horizontally, and vertical scanning may induce fatigue or what have you, but just because a screen is filling up our entire vertical range of vision, it does not mean we need to visually scan the whole image to take it in.

while we don't HAVE to scan vertically if the picture is within our peripheral field of view, we just do if there are things of interest there. We can of course debate the combinations of film conventions regarding how material is composed within the frame combined with various aspect ratios. Perhaps IMAX specific films intentionally don't place important subject matter at the vertical extremes for this purpose. I don't know, but I do know that the percentages of movies I watch in home that were filmed for IMAX is exceedingly low so this isn't even a remote concern for me.

SMPTE and THX recommendations are of course emperically derived and we can and do debate those. But in the abscence of some strong reason otherwise, I think they are as good a starting point as any.
post #37 of 114
Thread Starter 
Quote:
Originally Posted by Bigus View Post

"Some guy" must have had some odd lengthed fingers then! When I do that the result is more like 16:9, maybe even wider.

Only if you make the thumbs and fingers touch.
post #38 of 114
Thread Starter 
Quote:
Originally Posted by Bigus View Post

while we don't HAVE to scan vertically if the picture is within our peripheral field of view, we just do if there are things of interest there. We can of course debate the combinations of film conventions regarding how material is composed within the frame combined with various aspect ratios. Perhaps IMAX specific films intentionally don't place important subject matter at the vertical extremes for this purpose. I don't know, but I do know that the percentages of movies I watch in home that were filmed for IMAX is exceedingly low so this isn't even a remote concern for me.

SMPTE and THX recommendations are of course emperically derived and we can and do debate those. But in the abscence of some strong reason otherwise, I think they are as good a starting point as any.

I know someone will counter this before I write it, but...Most films don't place things of interest of the extreme ends of the film frame... especially in regards to the upper and lower limits.
post #39 of 114
I don't know about counter, buy I did mention it in the post you quoted.

Exactly how the composition os framed of course influences discussion about which aspect is most appropriate. Again, that's where I tend to take the standards organizations as probably having the best handle on that.
post #40 of 114
What about perspective dictating the ideal viewing distance like it does for viewing still photography pictures?

I am very unsure how you figure this out.
So my figures below maybe completely wrong.
I think still cameras and movie cameras calculate out differently because still cameras normal lens assumed viewer distance is different, the movie viewer is I think assumed to be half the distance of the still picture viewer, because they are between the projector and the screen. A cinema 35mm negative is half the size of a still photography 35mm negative, but they both use a 50mm lens as the standard lens.

My guess

Super 35mm is about 18.66mm height, 21.95mm width
My screen is 2.35:1 96" x 40.85" 2438.4mm width.
A magnification of 111.1x the super 35mm width
The normal (perspective correct same as vision) film camera lens is 50mm (about 2")
The normal lens for a film print projector is apparently 100mm 4" (because if a 50mm 2" lens was used the audience sat between projector and screen would be sitting too close and the perspective would look foreshortened, 100/50 = image half the size, audience sit halfway between projector and screen for correct perspective)
So that is 111.1 x 50mm focal distance /2 due to the projector lens for 2777.5mm 109.3" viewing distance.
109.3" viewing distance for my 2.35:1 96"x40.85" screen is 1.13x screen width, 2.67x screen height, horizontal field of view of 47.4 degrees

For normal perspective the diagonal of the negative gives the standard lens focal distance. My 2.35:1 96"x40.85" screen is 104.3" diagonal. 49.4 degrees horizontal field of view.

What is the rationale behind SMPTE reference of 43.4 degrees? Is it just a convenient figure 3x screen height for 2.39:1 aspect ratio?
post #41 of 114
Taking the chart posted by RichH and blanking out areas for best horizontal and vertical coverage one comes up with 2 AR.

The horizontally biased one is closest to 1.78:1 or 16:9 ( actually 1.80:1 approx)

The other closest to 1.33:1 or 4:3 (actually 1.20 approx)

But what is interesting is both those are almost identical in area, 74664 vs 76245 pixels.

Hmmmmmm..............!

Attachment 210505


LL
post #42 of 114
Quote:
Originally Posted by dovercat View Post

What is the rationale behind SMPTE reference of 43.4 degrees? Is it just a convenient figure 3x screen height for 2.39:1 aspect ratio?

Not 100% sure. I got a paper from them back in 2001 and they had 3x the image for TVs as well. I find it a very comfortable distance to sit. Right now, I am just loving their minimum of 2x the image height for films on my CIH system.
post #43 of 114
According to this Dolby labs paper, the 45 degrees recommendation way back in the 50s was where image quality and immersion met on a scale of best immersion and best quality. Closer was more immersive (a good thing it would seem), but too close and film artefacts (grain, dirt, scratches etc) and projector mechanics (weave, jump etc) started to become visible, so 45 degrees was where they suggested the best place to sit would be. Digital doesn't have the same issues, and is perhaps why THX suggest 40 degrees (2.4 x IH) for full HD 16:9 using good quality HD source material.

http://www.dolby.com/uploadedFiles/E...screensize.pdf

Gary
post #44 of 114
Quote:
Originally Posted by Gary Lightfoot View Post
A very interesting read. Thanks for that
post #45 of 114
Quote:
Originally Posted by CAVX View Post

A very interesting read. Thanks for that

You're welcome

Here's another one:

http://www.dolby.com/uploadedFiles/z...%20Picture.pdf

These are quite handy too:

http://www.cinemaequipmentsales.com/

The Dolby and THX links are probably the most useful (needs some navigation to get to the best bits).

Gary
post #46 of 114
Quote:
Originally Posted by Gary Lightfoot View Post

You're welcome

Here's another one:

http://www.dolby.com/uploadedFiles/z...%20Picture.pdf

These are quite handy too:

http://www.cinemaequipmentsales.com/

The Dolby and THX links are probably the most useful (needs some navigation to get to the best bits).

Gary

Nice finds!

WAY OFF TOPPIC: Gary I was surfing youtube and came across an old video from AVForums at the JVC head quarters in the UK and to my surprise there you were! I bet that was a fun experience. Have you been back for anymore viewings?

-Sean
post #47 of 114
Does it not strike one as strange that with BluRay, with CIH the source with more actual detail(16:9) is of a smaller size/area than the source with less actual detail(2.35:1)?......!!!
post #48 of 114
Quote:
Originally Posted by 230-SEAN View Post

Nice finds!

WAY OFF TOPPIC: Gary I was surfing youtube and came across an old video from AVForums at the JVC head quarters in the UK and to my surprise there you were! I bet that was a fun experience. Have you been back for anymore viewings?

-Sean

Hi Sean,

Yup, that was me

I hate being video'd etc and a lot of stuff I said about CIH and A lenses wasn't in the final video (either due to me or due to time constraints so was edited out).

It was a good day - met up with a few other enthusiasts as well as some dealers (Neil Davidson in particular who is very knowledgeable) and some JVC staff as well (a fleeting visit by GaryB who posts here). I could post a lot more info here regarding CIH, A lenses, seating distances and why they didn't zoom etc, but I won't as it's all been said before

I've not been back to the JVC though I did have an invite to another similar event there. I've a lot on at home unfortunately otherwise I would have gone.

Gary
post #49 of 114
Quote:
Originally Posted by Highjinx View Post

Does it not strike one as strange that with BluRay, with CIH the source with more actual detail(16:9) is of a smaller size/area than the source with less actual detail(2.35:1)?......!!!

Did it occur to you that the only reason Scope on BD is "smaller" with "less detail" is because of the limits of 1.78:1?
post #50 of 114
16:9 and 2.35:1 are the wrong way round purely for the reasons mark says. If there were more 2.35 displays, it might be different. Even Dolby says CIW isn't ideal (from one of the Dolby papers linked to above):

Quote:
Originally Posted by Dolby View Post

Certainly the practice of common width (i.e., a 1.85:1 image 35 percent higher than scope) is the wrong way around, and provides a great disservice to the projected image

Scope was designed to be the same height as existing screens, only wider:

http://www.widescreenmuseum.com/wide...sb2-page00.htm

Gary
post #51 of 114
Thread Starter 
Quote:
Originally Posted by Gary Lightfoot View Post
16:9 and 2.35:1 are the wrong way round purely for the reasons mark says. If there were more 2.35 displays, it might be different.
Regardless of "what should be", this is a pretty valid point. I, for one, would not be willing to give up image detail and picture quality just because "scope is supposed to be bigger."

What do you think the odds are of anamorphic blu-rays being introduced?
post #52 of 114
Thread Starter 
Furthermore, on that same note, it appears that the justification for the (rather arbitrary decided upon... in the 50s, mind you) 45 degree viewing angle offered in the aforementioned links is based upon a compromise between "involvement" and "quality." (ah, I see you touched on that already, Mr. Lightfoot.) However, adhering to that logic would mean that on the blu-ray format (as it is, with no anamorphic option as of yet), flat should actually be larger than scope since it, flat, has more image detail at the moment.

This quote:
Quote:
Certainly the practice of common width (i.e., a 1.85:1 image 35 percent higher than scope) is the wrong way around, and provides a great disservice to the projected image

states that it was a disservice because of the same, but opposite, issue with film. On film, scope actually takes up more of the film stock; flat takes up less, thereby having less image detail and making for a poorer quality picture when "blown up." With blu-ray, CIH is actually committing this same sin.
post #53 of 114
Quote:
Originally Posted by javanpohl View Post

What do you think the odds are of anamorphic blu-rays being introduced?

Hopefully they will be! That would be so nice to have an option to buy a blu-ray that is CIH ready. They offer 3d versions of movies, why not anamorphic? Then to go further, why not anamorphic-3d version? Where are these options? (I understand that there isn't a high demand for such options, but it would be nice!)

-Sean
post #54 of 114
Quote:
Originally Posted by javanpohl View Post

Regardless of "what should be", this is a pretty valid point. I, for one, would not be willing to give up image detail and picture quality just because "scope is supposed to be bigger."

What do you think the odds are of anamorphic blu-rays being introduced?

Why would you be giving up detail and quality just because the lowest resolution is making the larger image? Relatively speaking perhaps, but you're losing immersion and intent with CIW. It's also entirely relative to how close you like to sit compared to someone else.

As for anamorphic BD, I can't see it happening any time soon.

Gary
post #55 of 114
Quote:
Originally Posted by javanpohl View Post
Furthermore, on that same note, it appears that the justification for the (rather arbitrary decided upon... in the 50s, mind you) 45 degree viewing angle offered in the aforementioned links is based upon a compromise between "involvement" and "quality." (ah, I see you touched on that already, Mr. Lightfoot.) However, adhering to that logic would mean that on the blu-ray format (as it is, with no anamorphic option as of yet), flat should actually be larger than scope since it, flat, has more image detail at the moment.

This quote states that it was a disservice because of the same, but opposite, issue with film. On film, scope actually takes up more of the film stock; flat takes up less, thereby having less image detail and making for a poorer quality picture when "blown up." With blu-ray, CIH is actually committing this same sin.
Which ever way you want to play it, they're both a compromise, CIW because it's not the design intent, and CIH because we choose to use the lowest res for the largest image. Pick your poison.

Gary
post #56 of 114
Quote:
Originally Posted by javanpohl View Post

Regardless of "what should be", this is a pretty valid point. I, for one, would not be willing to give up image detail and picture quality just because "scope is supposed to be bigger."

No one is forcing you to go CIH if you don't want to. It may not be for everyone.

Your notion that you'd be "giving up image detail" is a fallacy, however. The image detail is what it is. A Blu-ray letterboxed to 2.35:1 has about 1920x815 active pixels whether you watch on a 16:9 screen or a 2.35:1 screen. Those pixels don't suddenly disappear when you zoom or scale the image up. Conversely, you're not going to get more than 1920x815 active pixels by watching on a 16:9 screen. It's an unfortunate reality that 21:9 anamorphic enhancement wasn't built into the Blu-ray format when it was developed, but that's not going to change whether you watch in CIH or CIW format.

You may argue that "picture quality" is degraded by zooming or scaling that 2.35:1 image to fill a 2.35:1 screen, but those of us who actually do this know that this is a negligible concern on Blu-ray, which holds up very nicely.
post #57 of 114
Quote:
Originally Posted by javanpohl View Post

Regardless of "what should be", this is a pretty valid point. I, for one, would not be willing to give up image detail and picture quality just because "scope is supposed to be bigger."

By that logic you'd be watching on an iPhone 4 with it's "retina display" than a large FP setup.
post #58 of 114
Quote:
Originally Posted by Josh Z View Post

No one is forcing you to go CIH if you don't want to. It may not be for everyone.

Your notion that you'd be "giving up image detail" is a fallacy, however. The image detail is what it is. A Blu-ray letterboxed to 2.35:1 has about 1920x815 active pixels whether you watch on a 16:9 screen or a 2.35:1 screen. Those pixels don't suddenly disappear when you zoom or scale the image up. Conversely, you're not going to get more than 1920x815 active pixels by watching on a 16:9 screen. It's an unfortunate reality that 21:9 anamorphic enhancement wasn't built into the Blu-ray format when it was developed, but that's not going to change whether you watch in CIH or CIW format.

That seems a somewhat uncharitable reading of javanpohl's post. While javanpohl could have phrased his concern better, it's obvious what he means is that with 16:9 Blu-Ray images (and virtually, with 1:85:1) you get all the available resolution of Blu-Ray devoted to re-creating the image, wheras with Scope on Blu-Ray you get fewer pixels to capture the entire movie image, hence with CIH you are indeed blowing up the lower resolution
image, which reverses the wisdom of having the higher resolution image as the larger image.

It's a legitimate complaint. Not a few people on this forum over the years have pointed out that, as much as they still like scope being the bigger image, that in terms of sheer image quality/clarity/density they have noticed that goes in favor to 16:9/1:85:1 images in their theater.

I vary my image sizes all the time and notice the same thing (and yes I've seen plenty of set ups using A-lenses).

It's not for nothing many of us - and certainly most CIH devotees - would welcome anamorphic Blu-Rays, which is essentially javanpohl's point.
post #59 of 114
Quote:
Originally Posted by stanger89 View Post

By that logic you'd be watching on an iPhone 4 with it's "retina display" than a large FP setup.


Yet if we take the alternate logic, and someone said "I for one would not want to give up a larger Scope image size just for picture quality" one could retort: By that logic you'd be fine watching an old VHS tape on a 200" projection screen.

That would be an equally uncharitable retort.

Surely you don't reject the idea that raising the image size puts pressure on source image quality/resolution. Blowing up a DVD to 130" wide is going to be a compromise in apparent image quality vs a good Blu-Ray, due to the lower resolution of the DVD.

You can regain a much better apparent clarity and image quality to the DVD by making it a smaller image.

And that isn't just confined to DVD. Blu-Rays as we know are quite variable in quality. And generally speaking the smaller you make your projected image, for a given viewing distance, the clearer and punchier the image will appear.

I use this fact all the time. Sometimes I'll watch Blu-Ray content in a very immersive size - 120" wide scope to 136" diag 16:9. Sometimes I'll watch the content much smaller, even down to 94" diagonal. Why? Because the apparent image quality in terms of sharpness, image density and vividness increases as the image is made smaller, which can be very appealing in of itself. (I especially like to watch some reality TV shows in HD that way - makes it feel like I have an extra big plasma on the wall). And I vary the image size per source quality. Some lesser Blu-Rays simply don't look as nice, full-size on my screen so I view them at a smaller size which preserves the impression of good image quality.

So, let's cut the guy a break: there is clearly some logic behind the tension between blowing an image up bigger and possible compromises in image quality.
post #60 of 114
Quote:
Originally Posted by R Harkness View Post

Surely you don't reject the idea that raising the image size puts pressure on source image quality/resolution.

That's the case whether he's talking about CIH or just talking about installing a bigger screen than whatever he has now. Of course there are going to be trade-offs that need to be taken into consideration when designing any theater room. But that doesn't mean he should write-off the whole notion of CIH (or of installing a screen 1 inch larger than he has now) based only on theory.
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