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The EF 500mm lenses are a group of super-telephoto prime lenses made by Canon that share the same focal length. These lenses have an EF type mount, and fit the Canon EOS line of digital single lens reflex cameras. When used on a camera with a field of view compensation factor of 1.6x, such as the Canon EOS 400D, they provide a narrower field of view, equivalent to an 800 mm lens mounted on a 35mm frame body. With a 1.3x body such as the Canon EOS-1D Mark III, they provide a less narrow field of view, equivalent to an 650mm lens mounted on a 35mm frame body. These lenses are most commonly used by sports and wildlife photographers. Three EF 500mm lenses have been available, and all are L series lenses. The most recent, the 4L IS II, released in 2012 and is the only model in production. * 4.5L USM * 4L IS USM * 4L IS II USM ==EF 500mm 4.5L USM== The EF 500mm 4.5L USM is a professional L series lens that is now discontinued. This lens is constructed with a metal body and mount, and with plastic extremities and switches. Features of this lens include a wide rubber focus ring that is damped, a distance window with infrared index, the ability to limit the focus range, a focus-preset mechanism, and the ability to set the AF speed. A 9 bladed maximum aperture of 4.5, gives this lens the ability to create depth of field effects. The optical construction of this lens contains 8 lens elements, including one fluorite lens element, and one UD (Ultra low Dispersion) lens element. This lens uses an inner focusing system, powered by a ring type USM motor. The front of the lens does not rotate nor extend when focusing. This lens is compatible with the Canon Extender EF teleconverters. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Canon EF 500mm lens」の詳細全文を読む スポンサード リンク
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