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

[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).

[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?

[Mark Gulbrandsen]

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

[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.

[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.

[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.

[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?

[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.

[Mark Gulbrandsen]

I have a D-150 lens question. I noticed some people on E Bay from time to time have a D-150 Kollmorgan Curvulon lens up for sale. It says It's for 70mm D-150 projection on the lens has no front extension cover tube. . I have seen other photos of a larger longer type D-150 lens that has a blue front wide cover that says in large letters D-150. Were there four types of lens made for D-150? 35mm flat, 35mm scope, 70mm and D-150 ?

Many people say the D-150 lens with the front long scope wide cover in blue weighed allot. The 70mm one on E Bay says It weight is 4 pounds.

. I hope to find for my movie collection the long heavy one with the blue ending tube one of these days. I only have 16mm Kodak projectors and a CinemaScope lens but still would like to have the D-150 type. I wonder if I can ever trace from the number printed on the lens what theatre it was used in.

Terry,
That is the lens they provided for Standard 70mm projection. It says Curvalon, not Super Curvalon like the big lens does. It still looks brand new, so doubt this lens got used much, if at all, as it just looks like a regular spherical lens and it would offer no correction for the deep curved screen unlike the Super Curvalon lens does. I had a 70mm reel from Patton, and the film itself had no correction on it like Todd-AO tried to do. In D-150's case, the Super Curvalon lens did the deep curve correction.

[Mark Gulbrandsen]

To me, Scope inside of Imax makes as much sense as mixing orange juice in to your coffee! A total waste...

[Vern Dias]

Vern, I like JRiver, but they tend to ignore posts that they have no interest in.

My current projector has the ability to store lens positions so I have just two set up to execute at the push of a button. One is scope and the other flat. It works fine most of the time, but they are so many aspect ratios on discs these day. There is always some adjusting to do. The worst are the IMAX releases that switch between scope and flat several times during the movie. Oppenheimer and Top Gun for example.

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.

[Mark Gulbrandsen]

I have one of the Blue Super Curvulon lenses, and it's at least 25 pounds if not more. And yes, all the lenses were provided in sets for a given theater. Both 35 and 70mm. Pretty sure Kolmorgen made them. I actually tried projecting 70mm on a 50 foot wide screen some years ago using the lens. The prime lens was the wrong focal length, but you could see the way it distorted the image to compensated for the deep curve.

[Ed Gordon]

Yep, that's my post. AFAIK, no action ever from JRiver on it, however....

Vern, I like JRiver, but they tend to ignore posts that they have no interest in.

My current projector has the ability to store lens positions so I have just two set up to execute at the push of a button. One is scope and the other flat. It works fine most of the time, but they are so many aspect ratios on discs these day. There is always some adjusting to do. The worst are the IMAX releases that switch between scope and flat several times during the movie. Oppenheimer and Top Gun for example.

[Terry Monohan]

I have a D-150 lens question. I noticed some people on E Bay from time to time have a D-150 Kollmorgan Curvulon lens up for sale. It says It's for 70mm D-150 projection on the lens has no front extension cover tube. . I have seen other photos of a larger longer type D-150 lens that has a blue front wide cover that says in large letters D-150. Were there four types of lens made for D-150? 35mm flat, 35mm scope, 70mm and D-150 ?

Many people say the D-150 lens with the front long scope wide cover in blue weighed allot. The 70mm one on E Bay says It weight is 4 pounds.

. I hope to find for my movie collection the long heavy one with the blue ending tube one of these days. I only have 16mm Kodak projectors and a CinemaScope lens but still would like to have the D-150 type. I wonder if I can ever trace from the number printed on the lens what theatre it was used in.

[Vern Dias]

Vern, I am a JRiver user and found this on there forum:



Source: https://yabb.jriver.com/interact/ind...topic=124128.0

Yep, that's my post. AFAIK, no action ever from JRiver on it, however.

Last I checked, JRiver allows you to only specify the zoom amount by percentages, whereas ZoomPlayer allows you to specify it by pixels.
JRiver also maintains a fixed relationship between amount of zoom in the x and y axis, Note, however that this is somewhat alleviated when using MadVR as it does have a parameter to specify the amount of horizontal expansion provided by the anamorphic lens.
Zoomplayer allows you to specify the amount of zoom in both the x and y axis independently.
MPV also allows separate x and y zoom parameters to be supplied. Although it also uses percentages, at least the percentages are not limited to integer values like in JRiver.

While I also have JRiver on my HTPC's I currently only use it when I need menu playback support. Zoomplayer is my daily use media player for playing physical media, mounted ISO files and MKV files.

I do use the MadVR beta with JRiver as MadVR is still state of the art for tone mapping with a much more configurable set of parameters, at least for my requirements. While JRVR, which uses the open source libplacebo code is close, MadVR is still noticeably more accurate, at least in my environment.

MPV is very flexible, but it is also tied the libplacebo for tone mapping. Although I have tested it extensively in the past, I currently only use it to play still photos in a slide show format.

I haven't tested VLC recently as it is also tied to libplacebo for tone mapping.