 |
|
 Home
Products
Store
Forum
Warehouse
Contact Us
|
|
|
|
This topic comprises 3 pages: 1 2 3
|
|
Author
|
Topic: Lens Types?
|
|
|
Frank Angel
Film God
Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999
|
posted 08-07-2004 09:29 AM
quote: Manny Knowles
A book I read in college explained that the purpose of the curved screen was to offset an optical defect in the original wave of CinemaScope lenses. If the screen remained flat, the image would appear slightly convex along the horizontal axis. In fact, I have seen a few 'scope movies on a flat screen and they do indeed appear to curve "away" near the left/right screen edges
Which just goes to show, Manny, that most of what we learned in college was crap.
The curve which was introduced in the CinemaScope system was there for three reasons, none of which had anything to do with correcting some early barrel-like distortions in the camera lenses. If you look at any of those early Scope features, the barrel distortion would be there no matter how much of a curve you projected them on, certainly the mild curve of the CinemaScope screens did not reduce it to any significant degree. However there were reasons for the curve, which, btw are still valid today.
1) Curving the screen is simple optics; it is a way to eek more light out of a system that was spreading the the same projector light output over twice the area of the non-scope picture. That is, in effect halving the light efficiency. Curving the screen (as well as making the screen a lenticular metalic surface, i.e., high gain silver material) would help overcome some of that light loss by directing more light back to the seating area. This curved screen and lenticular silver surface were manditory for the CinemaScope package -- Fox called it the Miracle Mirror Screen or some such. 2) The curve also helped in maintaining a more exact point of focus across the entire screen width. If you attach a string to the front lens of the projector out to the center of the screen, and then walk to the either side, the string will not reach to the corner, but will form an arc from the center to either end. The precise lens focus exists at any one point across that arc and not across a flat screen which finds its corners further away from the lens than its center. The curve screen places each point across the width quidistant from the projector lens, thus, theoretically, maintaining perfect focus. Lenses almost always have better depth-of-focus to more than compensate for the small error of a flat screen, nonetheless, the early Scope attachments made focusing quite critical so every little bit helped. And 3), the last reason why a curve screen was specified for any theatre playing CinemaScope came from the marketing department more than Fox's R&D department, and that was because the curve in the CinemaScope screen echoed the curve of the Cinerama deep curve screen which CinemaScope was desperately trying to mimic. CinemaScope was Hollywood's answer to Cinerama much more than it was to combat TV, which is the typical reason given for the introduction of wide screen and mulitichannel sound, and it is only partially correct. The much more dominant reason for developing CinemaScope was that major studios saw the lines going around the block, day in and day out at the Cinerama theatres which they were painfully aware were NOT owned and NOT operated any major studio, yet Cinerama had wildly captured the imagination of the public more than anything since the introduction of 3D. And the moguls wanted a piece of it so bad that they could taste it....and they wanted it cheap. CinemaScope was the poor man's Cinerama. Cinerama had a curved screen, and by Zanuck, so would CinemaScope.
| 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.
|
|
|
|
Printer-friendly view of this topic