Zoomar lens

Back developed an accessory "Vario-focus" viewfinder (designated PH-532/UF) for the Bell & Howell Eyemo camera variant PH-330-C issued by the United States Army Signal Corps during World War II; this incorporated many of the same principles as the commercial Zoomar lens, including the use of optical compensation.{{cite web |url=https://lift.ca/images/gear/1191.pdf |title=Camera PH-330-C Operating Instructions, Part Two, Section IV: Step-by-step operating procedure |publisher=United States Army Signal Corps |access-date=1 May 2023 |quote=Paragraph 58(g): Viewfinder PH-532/UF (Vario-focus). For full details concerning the installation, operation, and maintenance of this viewfinder, see TB Sig 159, Viewfinder PH-532/UF.}}

File:Back US2454686A (Zoomar, 1946).svg

Back applied for a patent in 1946 for a "Varifocal lens for cameras", which described the theory of its operation, using five sets of lenses: ordered from the object to the film, these were the front lens, variator, erector, compensator, and relay, with the variator and compensator mechanically fixed to each other and moving along the optical axis to vary the focal length; the other three sets of lenses remained stationary relative to the film plane. In the preferred embodiment, there were twenty-two lens elements in total:{{cite book |url=https://archive.org/details/historyofphotogr0000king/page/170/mode/2up |title=A History of the Photographic Lens |author=Kingslake, Rudolf |author-link=Rudolf Kingslake |date=1989 |publisher=Academic Press |location=San Diego, California |isbn=0-12-408640-3 |chapter=11: Varifocal and Zoom Lenses |chapter-url=https://archive.org/details/historyofphotogr0000king/page/152/mode/2up |url-access=registration |pages=153–174}}{{rp|170}} the front lens was a cemented group of two elements, the variator was an air-spaced group of four elements, the erector was an approximately symmetric set of eight elements in four cemented doublets, the compensator was a single cemented doublet, and the relay lens was an approximately symmetric air-spaced group of six elements.{{cite patent |country=US |status=Patent |number=2454686 |title=Varifocal lens for cameras |inventor=Frank G. Back |pridate=July 30, 1946 |pubdate=November 23, 1948}}

A prototype version was used by WCBS-TV on July 21, 1947 to cover the Brooklyn Dodgers / Cincinnati Reds game.{{Cite news|url=http://www.americanradiohistory.com/hd2/IDX-Business/Magazines/Archive-BC-IDX/47-OCR/1947-07-28-BC-OCR-Page-0032.pdf#search=%22zoomar%22|title=Fairbanks Reports Favorable Response To First Zoomar Lens Demonstration|date=July 28, 1947|work=Broadcasting / Telecasting|access-date=September 12, 2017}} The first commercial version was used by Paramount newsreel photographers to cover the 1947 World Series.{{Cite news|url=https://timesmachine.nytimes.com/timesmachine/1947/10/12/104345639.html?pageNumber=256|title=Betty Smith Looks at the South -- Garbo Considers|date=October 12, 1947|work=The New York Times|access-date=September 12, 2017}}

In 1949, WAVE-TV became the first television station in the United States, to present a live telecast of the Kentucky Derby. The telecast was the first use of a Zoomar Lens in a television sports broadcast. The lens was loaned to WAVE by Back. Not long after the Derby, WAVE acquired a Zoomar lens of its own, which was frequently loaned to the other stations owned by WAVE-TV.

File:Back US2913957A (Zoomar, 1959).svg

In 1968 Dr. Back bought the German optical firm Kilfitt from its owner Heinz Kilfitt, who retired. Kilfitt was one of the best and most innovative German lens makers of the 1950s and 1960s. The Münich factory started to produce the first production zoom lens in 1959 for 35mm still photography, the famous 36-82/2.8 Zoomar.{{cite magazine |url=https://books.google.com/books?id=UiYDAAAAMBAJ&pg=PA187 |title=Zoom Lens for 35-mm. Camera Shoots Still Photos |date=May 1959 |magazine=Popular Science |volume=174 |number=5 |page=187 |publisher=Popular Science Publishing Co., Inc. |access-date=13 March 2023}}{{Cite news|url=https://timesmachine.nytimes.com/timesmachine/1959/03/15/110085221.html?pageNumber=419|title=Zoom Lens For Stills|last=Deschin|first=Jacob|date=15 March 1959|work=The New York Times|access-date=September 12, 2017}} It was originally made in Voigtländer Bessamatic and Exakta mount. Most Kilfitt and Zoomar lenses left the factory with versatile interchangeable lens mounts.

In 1986 Zoomar left the civilian market, concentrating on US military optics.{{Citation needed|reason=Possible source is University of Rochester Institute of Optics special collection, but the only online source I could find is https://rollei-list-archives.eu/2001-05/00918.html, not reliable|date=December 2024}}

Frank Back was born in Vienna, Austria, in 1902; he earned bachelor's and doctoral degrees from the Technische Hochschule of Vienna and subsequently was employed by Georg Wolf, designing endoscopes. In July 1939, he emigrated to the United States. His varifocal lens design was an outgrowth of work he had previously performed for motion picture camera viewfinders and the projector part of a torpedo-targeting trainer.

In 1957, Ernie Kovacs published his novel Zoomar, named after the lens and billed as "a sophisticated novel about love and TV". The novel chronicles a network executive's descent into madness.{{cite web |url=https://revolutionoftheeye.umbc.edu/kovacs-in-the-public-eye-2/ |title=Kovacs in the Public Eye |website=Revolution of the Eye: Modern Art and the Birth of American Television |publisher=University of Maryland, Baltimore County: College of Arts, Humanities, and Social Sciences |access-date=1 May 2023}}

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• {{Commonscatinline}}
• [http://www.zoomlenshistory.org.uk/ Zoom Lens History]

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Category:Photographic lenses by brand