Film-Tech Cinema Systems


Film-Tech Forum


Post New Topic  Post A Reply
my profile | my password | register | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Question about D150 "Curvulon" Correction Lens (Page 1)

 
This topic comprises 2 pages: 1  2 
 
Author Topic: Question about D150 "Curvulon" Correction Lens
Frank Angel
Film God

Posts: 4759
From: Brooklyn NY USA
Registered: Dec 1999


 - posted 08-03-2011 08:40 AM      Profile for Frank Angel   Author's Homepage   Email Frank Angel   Send New Private Message       Edit/Delete Post 
There was an auction on ebay for the D150 Curvulon attachment (Kollermorgan). There's a very cursory description which mentions that the lens elements are ground so that there is a focus variant of about 10ft between the center and the edges of the screen, correcting the focus for the curve across the screen.

This seems to imply that the lens merely adjusts the focus to compensate for the distance difference between the left and right ends of the screen to the center.

My understanding of what the Curvulon lens did was to correct for the geometric distortion that the curve introduces into the picture. With the lens, the bowing of horizontal lines at the top and bottom of the screen is mostly eliminated and the horizon remains straight from top to bottom....at least that is what I remember being told years ago by a projectionist at the UA 150 in Long Island NY.

Maybe the lens corrects both focus and geometric distortion?

Anyone have any first hand info on this?

Here it is on ebay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200546534595&ssPageName=STRK:MEWAX:IT

I wish I had disposable income to buy this beauty. I'd build a curved screen just so I could use it -- actually I loved the D150 curve at that UA theatre. The Curvulon let them projector standard 35mm prints on it without any focus issues at all. 35mm scope looked really sweet on the D150 screen.

 |  IP: Logged

Bill Gabel
Film God

Posts: 3843
From: Technicolor NYC, NY, USA
Registered: Jan 2002


 - posted 08-03-2011 09:27 AM      Profile for Bill Gabel   Email Bill Gabel   Send New Private Message       Edit/Delete Post 
Here is some info on the lens.
D-150 Curvulon Lens

I have one from the UA Egyptian Theatre Hollywood. It's a Very Heavy Lens even without the backup prime lens in the rear.

 |  IP: Logged

Mark Gulbrandsen
Film God

Posts: 14422
From: Bountiful, Utah
Registered: Jun 99


 - posted 08-03-2011 09:28 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
I have one thats a decoration atop my dresser. You are correct in that it corrected geometric distortion. This is simply an attachment lens much like an anamorphic lens and a variety of Kollmorgen 4" diameter back up lenses screw directly on to it. The Kollmorgen back up lens on mine has an added aperature and one would assume that was the attempt to increase focus depth. The lens is way too heavy to mount in anything but a DP-70 and I'm pretty sure all the U.S. D-150 locations were DP-70 equipped. The lens could actually serve as an anchor for a small ski boat!

 |  IP: Logged

Brian Guckian
Jedi Master Film Handler

Posts: 594
From: Dublin, Ireland
Registered: Apr 2003


 - posted 08-03-2011 09:44 AM      Profile for Brian Guckian   Email Brian Guckian   Send New Private Message       Edit/Delete Post 
Here's a link Frank to an article written by Dr. Richard Vetter himself on the subject, over at in70mm.com:

[EDIT - I see Bill Gabel got there first!]

The projection field curvature was variable according to the spacing between the two lens doublets employed in the design.

Dr. Vetter states that with the appropriate choice of prime lens and the Super Curvulon lens set to the required magnification, the correct net focal length, field curvature and screen image width with precise focus center to edge were obtained.

It certainly would be a valuable acquisition.

A D-150 Super Curvulon lens is used to great effect at Pictureville, Bradford, UK when they do 70mm presentations on their Cinerama screen.

 |  IP: Logged

Bill Gabel
Film God

Posts: 3843
From: Technicolor NYC, NY, USA
Registered: Jan 2002


 - posted 08-03-2011 09:51 AM      Profile for Bill Gabel   Email Bill Gabel   Send New Private Message       Edit/Delete Post 
True most US D-150 locations were equipped with DP-70s. But there was a few locations that were equipped with DP-75s and Century JJ model projectors in the US.

 |  IP: Logged

Lionel Fouillen
Expert Film Handler

Posts: 225
From: Belgium
Registered: Nov 2002


 - posted 08-03-2011 10:22 AM      Profile for Lionel Fouillen   Email Lionel Fouillen   Send New Private Message       Edit/Delete Post 
The ODEON MARBLE ARCH in London had Cinemeccanica V8 projectors when it opened with D-150.
Scanned magazine about the installation

 |  IP: Logged

Bob Bregazzi
Film Handler

Posts: 17
From: Hampshie, England
Registered: Jan 2010


 - posted 08-03-2011 11:05 AM      Profile for Bob Bregazzi   Email Bob Bregazzi   Send New Private Message       Edit/Delete Post 
The Odeon Marble Arch was the first cinema i ever worked in. At the time i was there (1968. if i remember correctly the D150 picture size was 75'x 29'. At the time i was there Dr. Doolittle was showing in normal 70mm Todd-AO. Fox stipulated in the contract that no picture size could be as big as the D150, hence normal 70mm was about 68', which in itself looked lovely on that screen and I believe the normal 70mm lens were curvature corrected. There were 3 vic 8's. It used to be a beautiful theatre but was carved up into 5 screens.

 |  IP: Logged

Lionel Fouillen
Expert Film Handler

Posts: 225
From: Belgium
Registered: Nov 2002


 - posted 08-03-2011 12:28 PM      Profile for Lionel Fouillen   Email Lionel Fouillen   Send New Private Message       Edit/Delete Post 
Bob,
I saw The Temple of Doom and Lawrence' 1989 restoration in 70mm at Marble Arch. As far as I remember, The Temple was projected on the original curved screen on the standard surface you mentioned. Unfortunately for Lawrence, the screen had been flattened, they say at David Lean's request. Too bad it was split in 5 in the 1990's, although the original stage and front rows remain intact but underexploited by the new 35mm-only installation.

 |  IP: Logged

Bob Bregazzi
Film Handler

Posts: 17
From: Hampshie, England
Registered: Jan 2010


 - posted 08-03-2011 02:24 PM      Profile for Bob Bregazzi   Email Bob Bregazzi   Send New Private Message       Edit/Delete Post 
yes you are right Lionel, it was at DL's request, he was a wee bit perturbed by the amount of distortion on the desert scenes. I saw "close encounters" and "return of the jedi" both in 70mm. although the cinema was not in the "west end" it was always considered one in the early years, but being of the beaten track turned into a bit of a white elephant.

 |  IP: Logged

Lionel Fouillen
Expert Film Handler

Posts: 225
From: Belgium
Registered: Nov 2002


 - posted 08-04-2011 05:10 AM      Profile for Lionel Fouillen   Email Lionel Fouillen   Send New Private Message       Edit/Delete Post 
[YouTube] Odeon Marble Arch
Showing the flatter screen in what's left of the Odeon. In the new projection booth they built in front of the former circle, it seems they kept an original Vic projector, albeit with a new Christie lamphouse. But is it a Vic 8 ? I always thought Vic 8 never were built with single-lens holders. Could this be a Vic X ?

 |  IP: Logged

Louis Bornwasser
Film God

Posts: 4131
From: prospect ky usa
Registered: Mar 2005


 - posted 08-04-2011 11:04 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
I have used a Magnecom 65 pushed fully together for nearly the same effect. If you have a long enough f/l of the prime, it will pass 70mm film. The previous lens in this house was an old Cinemrama 70 lens. The deep curve screen needed the help. The Magnecom lens used this way caused the center of the picture to focus about 25 deet deeper than the sides.
At least the Schneider didn't change the color, and was much brighter than the Cinerama. Louis

 |  IP: Logged

Hillary Charles
Jedi Master Film Handler

Posts: 742
From: York, PA, USA
Registered: Feb 2001


 - posted 08-04-2011 01:56 PM      Profile for Hillary Charles   Email Hillary Charles   Send New Private Message       Edit/Delete Post 
This looks like one of those lenses in action.

The same poster also uploaded some other D-150 related pictures.

 |  IP: Logged

Bill Gabel
Film God

Posts: 3843
From: Technicolor NYC, NY, USA
Registered: Jan 2002


 - posted 08-04-2011 02:38 PM      Profile for Bill Gabel   Email Bill Gabel   Send New Private Message       Edit/Delete Post 
quote: Hillary Charles
The same poster also uploaded some other D-150 related pictures.
Yes, I did that yesterday on that site.

 |  IP: Logged

Hillary Charles
Jedi Master Film Handler

Posts: 742
From: York, PA, USA
Registered: Feb 2001


 - posted 08-04-2011 02:41 PM      Profile for Hillary Charles   Email Hillary Charles   Send New Private Message       Edit/Delete Post 
So you're the mysterious "William"! Small world! Thanks for sharing those great photos. [Cool]

 |  IP: Logged

Bruce Hansen
Jedi Master Film Handler

Posts: 847
From: Stone Mountain, GA, USA
Registered: Dec 1999


 - posted 08-04-2011 05:06 PM      Profile for Bruce Hansen   Email Bruce Hansen   Send New Private Message       Edit/Delete Post 
quote:
The lens could actually serve as an anchor for a small ski boat!

Mark. I have a small ski boat. would you like me to give that lens a try?

 -

[Big Grin]

 |  IP: Logged



All times are Central (GMT -6:00)
This topic comprises 2 pages: 1  2 
 
Post New Topic  Post A Reply Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



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.

© 1999-2014 Film-Tech Cinema Systems, LLC. All rights reserved.