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Optical Aids for High-Speed Photography
By DAVID C. GILKESON and A. EUGENE TURULA
Several new series of highly corrected lenses for high-speed motion picture and professional 35mm use have been designed with focal lengths ranging from 3.7 mm to 2000 mm. Mirror optics have been used for the longer focal length lenses. Particular optical design and fabrication problems are discussed with reference to mirror optics. Special optical devices to aid the high-speed photographer are discussed.
I
N ORDER to meet the many needs of professional users of 35mm motion picture cameras, Fastax cameras, 35mm still cameras and specialized applications of these cameras, several new series of lenses and aids have been developed. High-quality optical performance was a primary requirement because the lenses are to be used to record and study a variety of actions and instrument data over a wide field, for tracking, and for photographing and identifying distant objects in detail. The number of elements used in the construction of the lenses ranges from two to eleven (Tables I— V). The number necessary to achieve the performance desired is generally dependent upon the performance, aperture, and coverage requirements. The
Presented on October 10, 1952, at the Society's Convention at Washington, D.C., by David G. Gilkeson and A. Eugene Turula, Wollensak Optical Co., 850 Hudson Ave., Rochester 24, N.Y.
form and disposition of the elements within the system are dependent upon performance, aperture, coverage, space considerations, and special effects desired. With some exceptions, the number of elements used is no more than necessary and sufficient to meet the performance specifications of the user. The exceptions are the Raptar telephotos (Table II). It was much more important to have as short a back focus as possible for mechanical stability. If the back focus and general adaptability requirements were not important, achromatic doublets or triplets could have been used, depending upon the focal length.
The evaluation of lens performance by photographic resolution measurements has been well covered in previous papers.4"10 Such a test, however, measures performance of the lens-film combination and the result depends greatly on the methods, techniques and
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December 1952 Journal of the SMPTE Vol. 59