CONTAX CLUB Carl Zeiss 討論區

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文章發表於 : 週六 21 5月 05 10:05:26 
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註冊時間: 週六 08 11月 03 07:56:21
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鏡頭測試 Vol. 2 - 比較各年代之 Carl Zeiss 20mm and 21mm lenses

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1. 各鏡頭的一些基本資料 (感謝 Franka 整理)

Biogon 21/4.5 - Contarex mount

After WW-II, the 35mm film format fast became more popular both to the PRO and in general to the public. A need is arisen thus, for the system to cover a wide variety of focal length. Zeiss recognize this and re-commission their former lens designer L. Bertele to design an extreme wide angle for the then top of the line Contax RF. Bertele based his design on his work on the Wild Aviogon ( circa 1952, 115mm/4.5 for 180mm X 180 mm Aerial photography ) and come up with the famous post war 21mm/4.5 Biogon ( circa 1954 ). The lens consist of 8 elements in 5 group in a double reverse teleobjective design first pioneered and patented by M.M. Roosinov ( U.S.S.R. 1946 ). When Zeiss Ikon start the Contarex line in 1959, they realize a similar extreme wide angle is needed, but without their work done for the Distagon, they choose to remount the Biogon for the Contarex in a Mirror up fashion, and thus all Contarex and Contax Biogon are essentially the same lens in different mount.

Note : Both of the pre war & post war 35mm Biogon are completely different optical design and should not be confused with the 21mm Biogon

Biogon 21/2.8 - G mount

Zeiss re-introduce the Bertele Biogon formula when Kyocera introduce the G range in a 9 elements/7 groups configuration. The total re-design of the Biogon formula still retain the same basic optical layout as depicted in Roosinov's 1946 design but utilize notably a more aggressive asymmetrical design to further increase the speed.

Flektogon 20/4.0 - M42 mount

As the 35mm SLR system mature in the late 50's and early 60's , a recognition for extreme wide angle with proper SLR operation is needed. Carl Zeiss Jena ( East Germany ) was then a big time supplier of lens in M42 & Exakta and recognized for their technical prowness. To answer the call; CZJ applied the then relatively new Retro-focus design to their first extreme wide Angle in the form of 25mm/4.0 Flektogon ( circa 1961 ), and refine the system and launch the famous 20mm/4.0 Flektogon ( circa 1963 ) in a 10 Element / 6 group optical layout. For a long time this lens enjoy a famous and deserved followings because of its superlative performance against similar lens from other marque .

Flektogon 20/2.8 - PB mount

As all manufacturers of modern SLR lens do, CZJ recognize the deficiency of a pure Retro-focus design for extreme wide angle and incorporate refinement into the optical design by introducing a double tele objective into the optical design to their 20mm lens and thus born the up to date Flektogon 20/2.8 ( 9 elements / 8 groups ). It was introduced to the market on Dec 1979 together with the first of the PB lineup of SLR ( Praktica B200 )

Distagon 21/2.8

Zeiss Distagon is first introduced to the Contarex range in the form of 35/4.0, and utilize essentially a open end reverse tele-photo design. With the coming of RTS range. a need for an up to date 21mm is again needed. Zeiss, instead of working on the 25mm Distagon, takes the 18mm Distagon design and incorporate up to date technology in a 15 Elements / 13 groups new optical train. It should be noted, as in many modern lens of this focal length ( or shorter ) , the lens incorporate some design features from Fisheye & Retro focus design, notably the front elements to facilitate the oblique entrance of light. It should be noted that Distagon of 25mm and longer can generally be considered a single group opf Optical desgin while the 21mm and shorter are essentially a different ones.

2. 實拍照片 (感謝 章魚 協助測試)

拍攝資料 -

菲林: Fuji Superia 100
快門: 1/30s
光圈: f/16

#1 - Flektogon 20/2.8

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#2 - Flektogon 20/4

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#3 - Distagon 21/2.8

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#4 - Biogon 21/2.8

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#5 - Biogon 21/4.5

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3. 解像力比試

中心解像力

#1 - Flektogon 20/2.8

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#2 - Flektogon 20/4

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#3 - Distagon 21/2.8

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#4 - Biogon 21/2.8

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#5 - Biogon 21/4.5

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邊角解像力

#1 - Flektogon 20/2.8

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#2 - Flektogon 20/4

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#3 - Distagon 21/2.8

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#4 - Biogon 21/2.8

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#5 - Biogon 21/4.5

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有關討論請往:

http://forum.contax-club.org/viewtopic.php?t=4644

_________________
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Wah
理事 - Board of Members
www.flickr.com/dicksonlau


最後由 wah 於 週三 26 9月 07 01:59:52 編輯,總共編輯了 1 次。

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文章發表於 : 週二 24 5月 05 01:29:55 
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註冊時間: 週六 08 11月 03 07:56:21
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番外篇 - Distagon 21/2.8 vs Biogon 21/4.5

# Distagon 21/2.8

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# Biogon 21/4.5

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_________________
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Wah
理事 - Board of Members
www.flickr.com/dicksonlau


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