OPTICAL OBSTACLES IN SEARCH OF BUGEYE LENS

From The News

Tuesday, October 15, 1985

 

TODD -AO Southbridge痴 Role in the Movies - Second in a Series

 

The overall technical problem was to project a film onto a very wide screen without distortion.

Cinerama had gotten around the distortion problem with three cameras and three projectors.

To accomplish what Mike Todd wanted, a wide angle lens with a field of view of 128 degrees had to be designed. This was so a print could be projected to an equally wide angle and yet be essentially distortionless on a deeply curved screen when projected from the regular projection booth.

To help with the technical work, Dr. O達rien talked Dr. Walter P. Siegmund, who was doing post doctoral work at the University of Rochester, into taking a leave of absence.

Dr. Siegmund realized the challenge that faced him but still jumped at the opportunity. He has been with the AO and most recently Reichert Scientific Instruments in Southbridge ever since.

The technical problems were formidable just by themselves. But matters were complicated with a man like Todd, who always wanted things yesterday, hovering about.

To aid in expediting matters, O達rien called on his son, Brian O達rien Jr.

O達rien Jr. was accomplished in the field of optics in his own right but his contribution to the Todd-AO effort was primarily in the area of coordination - a very significant effort because of the multifaceted nature of the problem.

Walter Stewart, then president of the AO, with the backing of the board of directors, realized what O達rien was up against and did his part. O達rien was not only given a five-year contract but was also given carte blanche to use whatever AO personnel and facilities he felt were necessary to further the Todd contract.

O達rien took full advantage of this drawing on people from all over AO Southbridge and also from AO Buffalo and AO Keene, N.H. Naturally this ruffled some feathers.

Starting from scratch, O達rien and his people were able to get the whole job done including a world premiere of 徹klahoma! at the Rivoli Theatre in New York in just 36 months. This is a tribute not only to O達rien but to all of the other AO scientific and technical people who worked on the project.

In retrospect, while there are many who will say this period in AO痴 history was indeed traumatic, it probably was also one of its most vibrant periods.

Although O達rien kept very close personal supervision of every phase of the project, certain people came to have special responsibilities for carrying the project in given areas.

The Wide Angle Lens

To understand the problem facing O達rien, basic optics must be considered. All cameras consist essentially of a lens, a shutter, and a film plane.

The problem is that as the field of view gets greater, that is, as we can see over wider and wider angles, the distortions on the film increase and increase rapidly.

Dr. James G. Baker tried to solve this problem for wide angle aerial reconnaisance by using a lens that consisted of a series of concentric elements.

The imagery was indeed virtually perfect even for a field of view of nearly 180 degrees but, and what a big but this was, the imagery was perfect only if the film was on a hemisphere concentric with the lens.

This will work well on, say, an astronomical camera where we will take one picture and can then spend months examining the negative. For aerial reconnaisance where the scene changes rapidly or for motion pictures where we want many pictures of the same scene in a short space of time, a hemispherical film poses impossible obstacles in changing the film fast enough.

Further, in going from hemispherical to flat film without producing errors in angle or distance has been proved impossible by the mapmakers.

O達rien痴 lens problem is now getting clearer. We must not only see a very wide angle with the camera but we must squeeze the image onto a flat film.

One technique that has been around for some time is the anamorphic system. This approach, which was actually adopted by Twentieth Century-Fox in the fall of 1953, was rejected by O達rien.

He said in a recent telephone conversation, 典he trouble with the anamorphic system is that if a crowd comes toward you, you always see their faces head on whereas in actually they would appear in profile as they pass.

That is, it does not necessarily give the perspective of a true wide angle lens.

To augment the lens design capability of the AO, O達rien hired Dr. Robert H. Hopkins of the University of Rochester as a consultant.

AO had, of course, been involved with lens design problems for years and under people like Dr. Edgar D. Tillyer and Arthur Kavanagh in Southbridge and Robert Tackaberry and Richard Walters in Buffalo had built upon an envied reputation.

Initially in Southbridge, as elsewhere, the work had been done largely with scaled-up versions of desk calculators.

In 1953, in a move to update its lens design procedures, AO acquired first a card program calculator and then an IBM 650 computer. Both of these were monstrous by today痴 standards but they were just what Hopkins needed to design the complex 澱ugeye lens, as it came to be called, for the Todd-AO camera.

John Davis, now retired from the AO but still very active as an optical consultant, was manager of the optical computing facility. He relates that many a night he worked at the AO computer facility in Southbridge while it was connected to terminals in Hopkins bedroom in Rochester and Richard Walters office in Buffalo.

Basically, the bugeye lens is a reversed telephoto lens.

In actuality there were not three elements but 14. All of the surfaces had to be ground and polished and the elements then assembled with proper spacing. It is amazing that such a complicated lens could have been designed and fabricated so quickly. From the time Hopkins got the order to the time the lens had been designed, fabricated, tested and the patent filed was only a little over a year!