各個Nikkor AF標示的意義 尼康的自動對焦鏡頭是搭配著1985年第一台量產的自動對焦單眼相機F-501上市的。多年來隨著自動對焦技術的演進,尼康也推出了新款的Nikkor鏡頭。 不過即使是早期的AF鏡頭仍能和現在的自動對焦相機(包括數位單眼)搭配。尼康的AF鏡系有六大類標示來分辨其功能和特性:AF, AF-D, AF-I, AF-S, AF-G, AF DX AF是第一代Nikkor自動對焦鏡頭的名稱。這一版的鏡頭現在已經停產,但他們仍然能和新的相機搭配使用。自動對焦和複雜的TTL測光技術需要電子線路來連接相機及鏡頭。所以AF鏡頭都裝置有尼康稱之為中央處理器的微晶片。AF和手動對焦鏡頭很容易區分:機身上有刻AF字樣,而且鏡頭接頭處有一些電子接點。 Nikkor lenses: What do the various AF designations mean? Nikon have produced a variety of autofocus (AF) Nikkor lenses since the first mainstream AF Nikkors were introduced during 1985 to compliment the F-501 camera, which was Nikon's first mass produced AF SLR camera. Over the years, as AF camera and lens technology has evolved, Nikon has introduced new types of AF Nikkor lenses, although most of the earlier versions still remain compatible with current AF Nikon cameras, including the digital SLR models.There are six general designations that Nikon use to identify the features and functions available with each category of AF Nikkor lens; AF, AF-D, AF-I, AF-S, AF-G, and AF DX. AF The designation 'AF' was used on the first generation of AF Nikkor lenses, and whilst this type of lens has long since been discontinued there are many still in use and they remain compatible with most functions available all current Nikon autofocus SLR cameras. The introduction of autofocus technology and the continuing development of more sophisticated through-the-lens (TTL) metering systems required a far greater level of communication between a lens and the camera body. This could only be achieved by use of electronics, so each AF Nikkor lens contains what Nikon call a central processing unit (CPU), although to be strictly accurate it is in fact an encoding microchip that passes this information to and fro.It is easy to distinguish between an AF Nikkor lens and a manual focus Nikkor as the former has the 'AF' designation marked on the lens barrel and a series of electrical contact pins arranged around the rear flange of the lens mount. 各個Nikkor AF標示的意義 尼康的自動對焦鏡頭是搭配著1985年第一台量產的自動對焦單眼相機F-501上市的。多年來隨著自動對焦技術的演進,尼康也推出了新款的Nikkor鏡頭。 不過即使是早期的AF鏡頭仍能和現在的自動對焦相機(包括數位單眼)搭配。尼康的AF鏡系有六大類標示來分辨其功能和特性:AF, AF-D, AF-I, AF-S, AF-G, AF DX AF是第一代Nikkor自動對焦鏡頭的名稱。這一版的鏡頭現在已經停產,但他們仍然能和新的相機搭配使用。自動對焦和複雜的TTL測光技術需要電子線路來連接相機及鏡頭。所以AF鏡頭都裝置有尼康稱之為中央處理器的微晶片。AF和手動對焦鏡頭很容易區分:機身上有刻AF字樣,而且鏡頭接頭處有一些電子接點。 Nikkor lenses: What do the various AF designations mean? Nikon have produced a variety of autofocus (AF) Nikkor lenses since the first mainstream AF Nikkors were introduced during 1985 to compliment the F-501 camera, which was Nikon's first mass produced AF SLR camera. Over the years, as AF camera and lens technology has evolved, Nikon has introduced new types of AF Nikkor lenses, although most of the earlier versions still remain compatible with current AF Nikon cameras, including the digital SLR models.There are six general designations that Nikon use to identify the features and functions available with each category of AF Nikkor lens; AF, AF-D, AF-I, AF-S, AF-G, and AF DX. AF The designation 'AF' was used on the first generation of AF Nikkor lenses, and whilst this type of lens has long since been discontinued there are many still in use and they remain compatible with most functions available all current Nikon autofocus SLR cameras. The introduction of autofocus technology and the continuing development of more sophisticated through-the-lens (TTL) metering systems required a far greater level of communication between a lens and the camera body. This could only be achieved by use of electronics, so each AF Nikkor lens contains what Nikon call a central processing unit (CPU), although to be strictly accurate it is in fact an encoding microchip that passes this information to and fro.It is easy to distinguish between an AF Nikkor lens and a manual focus Nikkor as the former has the 'AF' designation marked on the lens barrel and a series of electrical contact pins arranged around the rear flange of the lens mount. 從鏡頭身上的D字母標示可以認出AF-D型的鏡頭 尼康推出了AF-D鏡系來支援1996之後的三維矩陣測光系統。外表上他和第一代的AF極為相似。但它運用鏡頭傳來的距離資訊來更精準地計算周遭的光強度還有閃光燈攝影的曝光量。D代表的是距離"distance"。所有AF-D之後的鏡頭(AF-I, AF-S, AF-G)都包含了AF-D的三維矩陣測光支援功能。所以也都在光圈值後面加了D字母,除了AF-G系列之外。 AF-I 為了大幅加快對焦速度和精確性,尼康有四款AF-I (I: internal 內部)鏡頭用內建的馬達,而非機身馬達帶動的連桿來對焦。這四款鏡頭是: AF-I 300mm f/2.8D AF-I 400mm f/2.8D AF-I 500mm f/4D AF-I 600mm f/4D 他們的鏡身和序號上都標示了AF-I。 To identify a D-type AF Nikkor lens look for the designation, which is shown on the barrel of the lens To provide full functionality with the 3D Matrix metering system that has been incorporated in Nikon camera models introduced since 1996, which uses the focus distance information as a component in calculations for both ambient light and flash exposures Nikon introduced the AF-D series Nikkor lenses. Although externally these lenses look very similar to the earlier type of AF Nikkor the internal microchip performs the additional function of communicating the focused distance of the lens to the camera body, hence the 'D' (D - distance) designation. Cameras compatible with Nikon's 3D Matrix metering system use this information to improve the accuracy of their built-in through-the lens (TTL) ambient and flash exposure metering systems.All current Nikon autofocus lenses communicate the focused distance information to compatible cameras capable of performing 3D Matrix metering and therefore conform to the AF-D specification, these include the AF-I, AF-S, and AF-G types. AF-D lenses can be identified by the 'D' designation in the description of the lens; this is marked on the lens barrel, and generally it is also shown as a suffix to the lens aperture value, which is also displayed on the lens except in the case of AF-G lenses. To improve the focusing speed of their autofocus lenses, particularly long focal length, wide aperture telephoto types, Nikon introduced the AF-I (I - internal) series of Nikkor lenses. Rather than using the focusing motor built-in to the body of an AF Nikon camera, which relies on a mechanical drive shaft link between the camera and lens to operate the focusing action, the AF-I type Nikkors have a coreless electro-magnetic focusing motor built in to the lens, which improves both the speed and accuracy of autofocus, significantly.Only four AF-I lenses were released: the AF-I 300mm f/2.8D, AF-I 400mm f/2.8D, AF-I 500mm f/4D, and the AF-I 600mm f/4D. All are clearly identified by the designation shown on the descriptive plate attached to the barrel of each lens that also displays the serial number of the lens. AF-G
AF-G鏡系不再有機械光圈環,G字尾放在最大光圈值後面尼康AF-G和所有的前輩最大的不同就是光圈環沒有了!尼康的市場調查顯示,越來越少人使用鏡頭上的光圈環。而且機身上的轉輪可以控制到三分之一級光圈,也遠比光圈環精確,無論攝影者的經驗如何。所以,尼康就在2000年推出了AF-G (G: Genesis “創世紀”)鏡系。最初這個系列是放在初級版鏡頭上,讓初學者能夠很容易的入門。而且它較輕,成本低,也方便大量生產。不過,尼康把這個系列推廣到專業鏡頭上。 包括了很受好評的AF-S VR 200mm f2 G IF-ED鏡頭。之後尼康的鏡頭也越來越多是沒有光圈環的G-type了。註:較早的尼康自動對焦相機無法從機身控制光圈,所以仍須要有光圈環的AF版本才能運用所有的測光模式。 DX系列使用反白字樣在機身上標示自從1999的Nikon D1開始有DX片幅(15.6mm x 23.7mm)起,尼康的DX鏡頭都是G-type的。 而且都支援三維矩陣測光。DX鏡頭的設計要點是盡可能讓光線接近垂直的射到感光板。另外,因為DX片幅面積較135片幅小,DX鏡頭都較輕較小。 The AF-G type Nikkor lenses can be identified by the absence of a conventional mechanical aperture ring, and the 'G' suffix after the lens aperture value The AF-G type Nikkor lenses differ from all other AF Nikkor lenses, significantly in one respect - they have no aperture ring.Apparently, based on the results market research, fewer and fewer photographers will use a lens aperture ring, if their camera/lens combination has the ability to adjust the lens aperture value by 1/3-stop electronically via a command dial on the camera, as this method is far more accurate than a manual aperture ring adjustment, regardless of the photographer's experience.As a consequence, during 2000, Nikon introduced the first examples of the AF- G (G - genesis) type AF Nikkor. Initially these lenses appeared as entry level models with a specification and price point intended for the consumer market, because they offered an number of benefits including being simpler to use by less experienced photographers, lighter, easier to construct, and therefore cheaper to mass produce.However, Nikon has extended the inclusion of the AF-G specification to several new professional AF-S lenses, such as the award winning AF-S VR 200mm f/2G IF-ED, and it is expected that this trend will continue across the Nikkor range as further lenses are released.Note: Earlier Nikon camera models that lack the ability to set the aperture value from the camera body require a Nikkor lens with an aperture ring to obtain full compatibility with all the exposure modes available on the particular camera in use. Each DX type Nikkor lenses has its designation marked clearly on the lens barrel Optimized for the DX format (15.6 x 23.7mm) sensor used in Nikon digital SLR camera models, which was first introduced with the D1 model during 1999, all six of the DX type Nikkor lenses released so far (mid-2005) are AF-G type lenses, and communicate the focused distance information to compatible cameras capable of performing 3D Matrix metering.The optics used in a DX type Nikkor lens is designed to ensure that after light leaves the lens it strikes the camera's digital sensor at the optimum angle. This requires the light rays to be perpendicular, or as close to perpendicular as possible relative to the surface of the sensor. Furthermore, since a DX type lens need only project an image circle that covers the smaller area of the DX format sensor rather than the larger area of a 135-format film frame they can be made smaller and lighter.© Simon Stafford http://www.simonstafford.co.uk/
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