Auto-Focus System for HDTV Field Lenses

Metadata

Publisher: SMPTE — White Plains, NY, USA
Doc Type: Journal Article
Content Type: Original Research
Abbreviated Title: SMPTE Mot. Imag. J
Volume: 117, No. 2, pp. 22–29
Abstract: The operation of a contemporary high-definition television (HDTV) lens-camera for sports and special events is a multifaceted task entailing close coordination of the camera operator with a program director and utilization of honed skills in picture framing, panning, and tilting, while maintaining a sharp focus on chosen objects within complex three-dimensional scenes The latter is made especially difficult by the absence of any true HDTV viewfinder; far higher focus sensitivity in HDTV than in standard-definition television (SDTV); and widely varying scene-lighting conditions calling for lens aperture settings that can shorten depth of field, all compounded at times by having to maintain that accurate focus on fast-moving objects within the scene. This imposes a significant strain on the camera operator, which can lead to considerable fatigue during extended shoots. This paper describes a powerful new auto-focus technology recently incorporated into two long zoom HDTV field lenses (today's zoom ranges for such lenses are on the order of 100:1 for sports coverage). The system borrows from a technology that has become central to digital still image single lens reflex cameras—called Secondary Image Registration Phase Difference technology. Sensing capabilities have been added that ensure a high accuracy in image-focus, while precisely maintaining that focus when tracking a fast-moving subject within the scene. Consistent HDTV sharpness is maintained thus freeing the camera operator to pay full attention to the important creative aspects of image framing and lens-camera positional manipulation with a lowering of fatigue.
Publication Date: 2008-03-01
DOI: 10.5594/J16000
ISSN: Print: 1545-0279 | Electronic: 2160-2492
Link: https://doi.org/10.5594/J16000
Author(s): Laurence J. ThorpeBroadcast and Communications Division of Canon U.S.A.
bio
Laurence J Thorpe joined the Broadcast and Communications Division of Canon U.S.A., Inc., in 2004 as national marketing executive. Before that, he worked at Sony Electronics, where he spent more than 20 years in HDTV development. Thorpe also worked for RCA's Broadcast Division from 1966 to 1982, where he developed a range of color television cameras and telecine products. He holds ten patents from this period. From 1961 to 1966, Thorpe worked in the Designs Dept. of the BBC in London, England, where he participated in the development of a range of color television studio products. Thorpe graduated from the College of Technology in Dublin, Ireland, in 1961, with a degree n electrical engineering. He received his Chartered Engineer (C. Eng.) and MIEE distinction in 1965 from the Institution of Electrical Engineers in London, England.
Yasuyuki TomitaBroadcast Equipment Development Center of Canon Inc., in Utsunomiya Japan.
bio
Yasuyuki Tomita is manager of the Broadcast Equipment Development Center of Canon Inc., in Utsunomiya Japan. He has been involved with the optical design of broadcast application zoom lenses since he joined the Broadcast Equipment Division's R&D Group of Canon Inc. in 1990. Tomita has designed lenses for sport production, studio production, and portable ENG applications. Recently, he has been involved with the development of AF technologies and other new optical technologies planned for use in broadcast television lenses.
Ken ItoBroadcast Equipment Development Center of Canon Inc., in Utsunomiya Japan.
bio
Ken Ito received a degree in mechanical engineering from the University of Waseda, Tokyo, Japan, in 1985. He immediately joined Canon Inc. where he worked in the R&D group on mechanical design of portable ENG lenses. In 1992, Ito transferred to the Broadcast & Communications Division of Canon U.S.A., where he is currently director of product management and administration. During this period, he has been the principal technical liaison—on all broadcast lenses and the CanoBeam laser transmission system—between the U.S. marketing requirements and the R&D group in Utsunomiya, Japan.
Copyright: © 2008 Society of Motion Picture and Television Engineers, Inc.

Bibliographic Reference(s)

1. Wada Masao , “development of the Precision focus assistance System for the HDTV Zoom Lens field Operations,” Presented at the SMPTE advanced Motion Imaging Conference, Chicago, IL, Feb. 26–29, 2004 . EXTERNAL
2. Calabro Thom , “Fujinon's Precision focus assist System,” Broadcast Engineering , June 2005 . EXTERNAL

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Laurence J. Thorpe, Yasuyuki Tomita, and Ken Ito; Auto-Focus System for HDTV Field Lenses, SMPTE Motion Imaging Journal ( Volume: 117, Issue: 2, March 2008); SMPTE, 2008. Available at https://doi.org/10.5594/J16000

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Laurence J. Thorpe, Yasuyuki Tomita, and Ken Ito; Auto-Focus System for HDTV Field Lenses, SMPTE Motion Imaging Journal ( Volume: 117, Issue: 2, March 2008); SMPTE, 2008. Available at https://doi.org/10.5594/J16000

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<span class="citation">Laurence J. Thorpe, Yasuyuki Tomita, and Ken Ito; <cite>Auto-Focus System for HDTV Field Lenses</cite>, SMPTE Motion Imaging Journal ( Volume: 117, Issue: 2, March 2008); SMPTE, 2008. Available at <a href="https://doi.org/10.5594/J16000" target="_blank" rel="noopener">https://doi.org/10.5594/J16000</a></span>

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Laurence J. Thorpe, Yasuyuki Tomita, and Ken Ito; Auto-Focus System for HDTV Field Lenses, SMPTE Motion Imaging Journal ( Volume: 117, Issue: 2, March 2008); SMPTE, 2008
doi: 10.5594/J16000
url: https://doi.org/10.5594/J16000

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<li>
Laurence J. Thorpe, Yasuyuki Tomita, and Ken Ito; <cite id="bib-10-5594-j16000">Auto-Focus System for HDTV Field Lenses</cite>, SMPTE Motion Imaging Journal ( Volume: 117, Issue: 2, March 2008); SMPTE, 2008
<span class="doi">10.5594/J16000</span>
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