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The EF 100–400mm 4.5–5.6L IS USM is a professional EF mount telephoto zoom lens manufactured by Canon Inc. The first version of this lens was announced in September 1998, and an updated version was announced in November 2014. It is a high performance telephoto lens most often used for sports and wildlife photography; the original version has received high ratings from purchasers at Amazon.com〔 and B&H Photo Video.〔 Photographers using APS-C cameras must apply a crop factor of 1.6x, giving the lens a field of view equivalent to a 160–640mm lens. Whilst the original version has excellent optical performance, its design predated the mass-market availability of digital single-lens reflex cameras. The telescoping nature of the original design means that the lens zooms quickly, although not all users prefer this design.〔 According to Roger Cicala, the head of the American lens rental house ''LensRentals.com'', The telescoping design means that the lens sucks in air when zoomed from shorter focal lengths to longer focal lengths. Unfortunately, with the lack of anything to prevent it, it also sucks in any airborne dust.〔Canon published lens data — The EF 70–200mm f/2.8L IS; EF 70–200mm f/4L IS USM and EF 70–300mm f/4.5–5.6L USM () have dust sealing. The published data shows that the 100-400mm () lacks this sealing.〕 Although this was not considered a problem when used with cameras that used photographic film, the dust can settle on the sensor of digital cameras leaving a permanent mark on every subsequent photograph until it is cleaned off. Newer cameras with dust removal systems have mitigated this problem somewhat.〔For example: Canon 50D Owners manual - Appending Dust Delete Data (Page 149)〕 This lens is compatible with the Canon Extender EF teleconverters on newer EOS bodies. Autofocus works with the 1.4× Extender (and only with cameras that can autofocus at f/8) and image stabilization (IS) works with both 1.4× and 2× Extenders. The new Canon EF 100-400 f/4.5-5.6L IS II was announced on 11 November 2014 (10 November in the United States due to time zone differences from Japan), with availability expected the following month. Among the changes from the Mark I version are: * The zoom mechanism now uses a rotating ring (like most other Canon zoom lenses), instead of a push/pull system. * The Mark II version also features a new lens hood with a side window, making it possible to adjust specialty filters (such as polarizers and variable neutral-density filters) without removing the hood. * The tripod mount can now be removed while the lens is attached to a camera body. The Mark I tripod mount can only be removed when the lens is detached. * The IS system has three modes instead of the two modes of the Mark I. The third mode (which Canon calls "Mode 3"), designed with action shooting in mind, except that stabilization is applied only during exposure. Previously, Mode 3 was available only on recent Canon supertelephoto lenses. == Specifications == 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 100–400mm lens」の詳細全文を読む スポンサード リンク
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