I guess Cinerama had to continue on some how...

[Jim Cassedy]

When I was a kid, I used to pass the Syossett D-150 theater on a regular basis, whenever I could
convince my dad to drive me to the big Lafayette Radio Electronics store, which was only about a
mile down the road from the D-150. A trip to Lafayette Radio was almost as good as day at Disneyland
for me back then. For many years, Norman Slotnick was the main projectionist at the Syossett D-150.
Norman was a good friend, and was the guy who sponsored me into the projectionists union, since at
that time it was pretty much impossible to work a New York booth without a union card. Aside from
occasionally dropping in to see him and to hang out in the D-150 booth (which was also almost like
Disneyland to me) I actually got to work several shifts there in the late 1970's, when it was still
considered one of the "A-List Prestige Booths" to work on Long Island. Whenever they didn't have
a D-150 or first run flick to show, they'd run a 70mm print of"Gone With The Wind". I think they
actually had their own print, since I never saw it leave the theater.

I ran that GWTW print several times there. & also worked one of the EARTHQUAKE (Sensurround)
shows there on short notice when either Norman or one of the regular relief projectionists couldn't
make the shift for some reason. "The Union" didn't just send anybody over there. . you had to be
pretty high up on the seniority roster, and also have a good projection reputation. I filled both
qualifications, but I'm pretty sure Norman might have put in a good word for me also. I never
actually got to run a D-150 print while I was there, but I do recall taking one of the lenses over
to the rewind bench & giving it a good inspection to satisfy my curiosity. I think it was at the
D-150 where I saw my very first Dolby-Stereo installations- - a CP-200, since the Syossett
projected some 35mm mag sound, and of course 70mm was all magnetic back in those days.

[Ed Gordon]

The repeatability issues of the lens mechanical zoom / shift along with the fact the the screen illumination is different for flat vs scope and requires separate calibrations has always made this approach a non-starter for me.

The IMAX releases are all shot Scope-safe since the majority of theatres in the world are not IMAX capable and they run them at 2.40:1. I also run them at 2.40:1. Oppenheimer and Top Gun look fine in this mode as the top and bottom of the image are superfluous.

Vern, I found this video which demonstrates using JRiver and MadVR on an HTPC to remove horizontal black bars on a constant height screen. Is this what you are doing to avoid zooming to keep the horizontal black bars off the screen?

[Vern Dias]

That's one way to do it. It looks like it doesn't require using an anamorphic lens. The downside is a loss in brightness because you are not using the entire imaging area of the panel in the projector.

I do it somewhat differently in that I do use an anamorphic lens which means that I get the maximum screen brightness the PJ is capable of .

Since I was fortunate enough to find a pre-prodction ISCO Cinema DLP 1.5x horizontal expansion anamorphic lens in a surplus outlet about 15 years ago, my screen AR is actually 2.76:1 which allows me to avoid any black bars even on UltraPanavision titles.

PXL_20211110_193502988.jpg

I do use MadVR for upscaling HD to 2160x3840 which is my projectors native AR and also for tone mapping 4K HDR.

It works with any Directshow player, including JRiver. However, I use Zoomplayer which allows more flexibility with up to 10 aspect ratio presets controlled by hot keys.

An example from my Zoomplayer conffig:

"Preset1"="1.77: XOfs[0] YOfs[0] Width[1920] Height[1080]"
"Preset2"="1.85: XOfs[-44] YOfs[-22] Width[2000] Height[1122]"
"Preset3"="2.00: XOfs[-109] YOfs[-70] Width[2130] Height[1220]"
"Preset4"="2.20: XOfs[-233] YOfs[-132] Width[2380] Height[1344]"
"Preset5"="2.40: XOfs[-333] YOfs[-190] Width[2580] Height[1460]"
"Preset6"="2.55: XOfs[-388] YOfs[-238] Width[2690] Height[1552]"
"Preset7"="2.76: XOfs[-515] YOfs[-300] Width[2940] Height[1684]"1


I prefer to select the AR manually from my remote control (HTWebRemote) since there are cases where the AR of the media does not accurately represent the intended projection AR of the title. For example, VistaVision titles, which are usually 1.77:1 or 1.85:1 on disc were originally intended to be projected at up to a 2.00:1 AR in theatres, and that's what I prefer in my HT. I've also found that many of the IMAX shorts that were originally 1.44:1 on film and transferred to video at 1.77:1 can be viewed very satisfactorily at 2.00:1.


Screenshot 2024-07-29 at 22-46-58 HTWebRemote.jpg

I hope this helps to explain my methodology for maximum immersion while totally filling the screen height at all times. Note that my preferred seating is 8' from my 52"x144" screen, so it's a pretty extreme viewing angle. It just takes me back 70 years or so, watching "This Is Cinerama" from the 4th row orchestra and I wouldn't have it any other way.

[Steve Guttag]

Ed, you're a man after my own heart -- GREAT video! How great to be able to get that awesome curve screen look and feel.

More than once over the years,my colleagues question me about my slightly obsessive preference for using a curve screen rather than a flat one, and I give exactly your demonstration but on a flat screen and with a string instead of a measuring tape. Doing it with flat screen is even a bit more dramatic because as you get to either end, the string is no longer touching the screen. So the question is, assuming a projection lens focal point is equidistant across the entire screen, then it follows that if the sides of the screen are farther away from the projector than the center. Therefore, when you rack the lens so that the image is perfectly in focus at the center of a flat screen, it follows theoretically, that the sides would be slightly out of focus, but not so on the curved screen where the lens-to-screen distance remains constant across it's entire width. But it is not; It seems we easily achieve fairly consistent focus end-to-end across a flat screen. How can this be, and if that were NOT the case, I would have pulled out my hair long before it fell out on its own.

Frank, that is not how lenses work, unless designed for something different, a standard lens is going to want to project the same shape it is seeing on to the surface it is projecting. That is, if the source image is flat, the projection will want to be flat too. You aren't sending the light just from some central point of the lens, the light entered the lens and exited it...you have to allow for how it entered too. So, if it is a flat plane (e.g. digital cinema imager), then it will be a flat shaped image coming out.

But wait, most film projectors have a curved gate. Actually, that would compound the issue as it is curved away from the lens...which would want to have resulting image with a convex curve. Indeed many Kollmorgan lenses will focus better if the screen is slightly convex.

Now a lens maker can take into account the curve of the film gate though you can't go too crazy with it as it is only curved in one direction and at the point of the aperture, the radius is normally very long (mostly flat). When you curve the screen, you are curving in other dimension too (screens tend to be curved horizontally while most film gates curve vertically). Just how are you supposed to make a lens that works with that without it being an anamorphic, of sorts? So, curved field lenses concentrate on the major axis and end up distorting the minor one. Adding in any keystone distortion from a non-centered projector just adds into the geometric distortions.

I like curved screens too but they are a struggle. I don't like the geometric distortions they bring. One thing I'm hoping for in the emissive screens is the ability to have a curved, distortion free (with respect to geometry) image.

Your notion that a curved screen will help with focus is a false one. Most likely it hurts a bit. It all depends on the lens, how it was design and gate of the projector and how it was design and all combined with the light system and how it passes through the film and into the lens. You have to look at it holistically.

[Marcel Birgelen]

Every cinema that managed to project the THX Broadway trailer, the one with the big blue box around the THX logo with minimal distortions on a curved screen used to get my highest regards.

Besides direct view screens, another way to manipulate your screen geometry digitally is using stuff like Christie Mystique, which is available for a select number of there more recent DCI projectors. It allows you to digitally stretch and deform the image at will.

Obviously, any kind of digital image manipulation will come at a loss in image quality, but it can be a solution for deeply curved screens with projectors at odd angles.

[Mark Gulbrandsen]

The Kolmorgen back up on my D-150 Lens actually has an aperture in it... But probably only a stop or two...

[Mark Gulbrandsen]

Every cinema that managed to project the THX Broadway trailer, the one with the big blue box around the THX logo with minimal distortions on a curved screen used to get my highest regards.

Besides direct view screens, another way to manipulate your screen geometry digitally is using stuff like Christie Mystique, which is available for a select number of there more recent DCI projectors. It allows you to digitally stretch and deform the image at will.

Obviously, any kind of digital image manipulation will come at a loss in image quality, but it can be a solution for deeply curved screens with projectors at odd angles.

Marcel.... I thought DCI forbid altering image shape? That's what I was told at one of my training classes... Did they finally give in?

[Steve Guttag]

News flash...there isn't any DCI police. If it doesn't violate security, they aren't going to stop anything and nothing at the theatre level will ever be inspected (unless it shows up as pirated content).

[Ed Gordon]

That's one way to do it. It looks like it doesn't require using an anamorphic lens. The downside is a loss in brightness because you are not using the entire imaging area of the panel in the projector.

I do it somewhat differently in that I do use an anamorphic lens which means that I get the maximum screen brightness the PJ is capable of .

That is correct, no anamorphic lens used. The only media that benefits from using anamorphic are those few DVD's that were encoded anamorphic..

Anamorphic, 16 x 9, enhanched for widescreen TV's were different slogans manufacturers used to describe that a DVD was also formatted 16 x 9 within the disc. DVD is a 4 x 3 format and including the movie in 16 x 9 on the same disc increased the vertical resolution by 33%. It was a way for manufacturers to increase the quality of the DVD video. There is no need for anamorphic since Blu-ray is high definition 1080P/24 or 1080i/60 or 1080i/50.

480i:
3 x 4 Letter box = 172,800 259,200 pixels (360 x 480 720 x 360 skinny pixels
16 x 9 anamorphic: = 337,920 345,600 pixels (704 x 480) 720 x 480 fat pixels

1080P
HD Blu-ray: = 2,073,600 pixels (1920 x 1080
HD Blu-ray letterbox = 1,568,640 pixels (1920 x 817)

Source: https://www.hometheaterforum.com/com...bluray.324364/

I did some initial testing and set my HTPC desktop to 1920x826 (2.35). Doing this solved three problems; (1) I don't have to zoom out to fill my scope screen, and media in other AR's (1.33, etc) still fill the screen without horizontal black bars and (2) when the letterboxed content ends there is no light spilling off the top and bottom of the image, and finally (3) since my desktop is no longer 16:9, the top and bottom of the desktop is not off the screen as is was when I had to zoom for wider aspect ratios on my 2.35:1 screen.

[Vern Dias]

That is correct, no anamorphic lens used. The only media that benefits from using anamorphic are those few DVD's that were encoded anamorphic..



Source: https://www.hometheaterforum.com/com...bluray.324364/

I did some initial testing and set my HTPC desktop to 1920x826 (2.35). Doing this solved three problems; (1) I don't have to zoom out to fill my scope screen, and media in other AR's (1.33, etc) still fill the screen without horizontal black bars and (2) when the letterboxed content ends there is no light spilling off the top and bottom of the image, and finally (3) since my desktop is no longer 16:9, the top and bottom of the desktop is not off the screen as is was when I had to zoom for wider aspect ratios on my 2.35:1 screen.

"That is correct, no anamorphic lens used. The only media that benefits from using anamorphic are those few DVD's that were encoded anamorphic.."

Actually that's kinda like comparing apples and oranges: Anamorphic pixels on a source media vs using an anamorphic projection lens to provide the horizontal stretching and then vertically stretching (scaling) the letterboxed source to fill the full 1080 or 2160 height of the projector's imaging panel .

Using an anamoprhic lens allows you to illuminate an additional 487,680 pixels of the 2,073,600 pixels on an HD projector's imaging panel for that 2.35:1 image which will deliver a substantial increase in screen brightness and the pixel density of the image on the screen.

Of course, this advantage all comes with the $ associated with purchasing an anamorphic lens.

[Marcel Birgelen]

Marcel.... I thought DCI forbid altering image shape? That's what I was told at one of my training classes... Did they finally give in?

Like Steve already indicated, there is nothing in the specs that doesn't allow for this, as long as DCI security isn't compromised. Also, when you've used anamorphic lenses with DCI in the past, you already stretched the picture over the entire height of the imager, hence you already altered the shape of the image by stretching it.

The only thing DCI explicitly forbids, and which I still think is utterly stupid is anything but "square pixels" in the DCP container. Non-square pixels with anamorphic lenses could fix scope in DCI, where we not only maximize light output, but also maximize the horizontal resolution and avoid any real-time scaling that potentially introduces new artifacts. Unfortunately, the scope-route in DCI essentially died a silent death after most manufacturers decided to abandon their support for it.

Still, if you need to do image manipulation to compensate for some challenging geometrics that can't easily be solved with optics, Christie's CineLife series DCI projectors in combination with their Mystique add-on software, is currently the only viable, DCI-certified route, although as you may expect, not entirely cheap.

[Mark Gulbrandsen]

News flash...there isn't any DCI police. If it doesn't violate security, they aren't going to stop anything and nothing at the theatre level will ever be inspected (unless it shows up as pirated content).

Steve, I was told by a guy from DCI at a CinemaCon a ways back that they limited the range of some adjustments in their guide to manufacturers. That's why I was wondering...

[Marcel Birgelen]

Steve, I was told by a guy from DCI at a CinemaCon a ways back that they limited the range of some adjustments in their guide to manufacturers. That's why I was wondering...

About the only test in the whole DCI test plan regarding image transformations is a test where a projected circle has the same with and height and is in fact, displayed as a circle and not an ellipse or other deformed form. About 95% of those specs and tests are about DCI security...