|
|
This topic comprises 3 pages: 1 2 3
|
|
Author
|
Topic: Tri-Circle Autoscope Drive-In Theater
|
|
|
|
|
Jerry Chase
Phenomenal Film Handler
Posts: 1068
From: Margate, FL, USA
Registered: Nov 2000
|
posted 04-03-2002 10:16 AM
Steve and John, I don't understand why you think there was a primary lens?The cone of light going through film from the reflector not only forms a cone of light within the lamphouse and throat, it forms another cone of illumination on the opposite side of the film plane.
Note the position of the lenses in the photographs. They all fall within this cone. It doesn't matter whether a lens is placed 3" from the film plane or 3', provided the focal length is correct, the lens will form an image that will be focused at a given distance. If that lens is within the cone of illumination it will probably form a bright enough image to comfortably view. There is no reason why more than one lens can't be placed to form images. In a theatre, we are used to one lens, partly because of the setup, and partly because multiple large lenses close to the film plane would be at an unacceptable angle to the film. I'm fairly sure that each of the small long focal length lenses "sees" the small frame illuminated within the gate without the use of additional optics. Remember we're talking about making small images on small screens. My original LOL! comment was because of the simplicity of the whole setup.
| IP: Logged
|
|
Steve Kraus
Film God
Posts: 4094
From: Chicago, IL, USA
Registered: May 2000
|
posted 04-03-2002 09:27 PM
Jerry, you may be on to something. The problem I have with the aerial image is that I don't think the little lenses would pick up the entire image, only a portion. An aerial image is in focus at a point in air. But beyond that point the light rays are just diverging.
I recall playing with the concept of aerial images with a 16mm portable machine. I focused the regular lens so closely (lens forward almost out of its mount) that the image was only a bit larger than the film frame. Move the temporary focusing object out of the way and hand holding another lens in front (just as far from the aerial focal plane--an inch or two--as the 2nd lens would normally be from a film plane to focus on the wall a few feet away). This would project a normal image (perhaps upside down; I've forgotten). As I recall, the key to this totally pointless exercise was that the aerial image was small enough to get picked up by the 2nd lens (which was just another 16mm projector lens) without vignetting. If I refocused the 1st lens so the in-focus aerial image was larger, I could still pick it up with the 2nd lens but only a portion of it, not the whole picture.How that applies here is that if there is an aerial image at some small distance below the cluster of small lenses, the small lenses would only pick up tiny segments of the picture. Looked at another way, if I focus a projector to produce picture about a foot or two across and then take the screen away, at any point at the screen level an observer can only see the light directed at that point, not the entire image. There will be a cone of light converging to that spot from across the width of the lens but originating from tranmission through a single point on the film.
| IP: Logged
|
|
|
|
|
|
|
|
|
|
Tim Reed
Better Projection Pays
Posts: 5246
From: Northampton, PA
Registered: Sep 1999
|
posted 01-04-2004 12:12 AM
Brad, that one down in Houston ran until about 1987, but I've heard it's just an empty field now. I saw it in '85, and it was about the coolest thing I'd ever seen. An outfit in MO "licensed" them. The TRAD Co., I believe it was called (Theatre Research and Development).
The projection system was just a standard 35mm projector with a large reel transport... nothing fancy, but the trick part was the mirror arrangement it projected into, up in that overhead dome. Wouldn't be too hard to make one, just time consuming getting it all adjusted. Needed a de-humidifier up there, too, to prevent fogging.
Most of the late Autoscope theatres were porn, because they couldn't show anamorphic pictures. They figured out a way to project scope in their last couple of years, but it was too late in the game.
| IP: Logged
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
All times are Central (GMT -6:00)
|
This topic comprises 3 pages: 1 2 3
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|
Home
Printer-friendly view of this topic