CONTAX CLUB Carl Zeiss 討論區

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文章發表於 : 週一 15 12月 03 10:45:51 
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註冊時間: 週一 08 12月 03 13:46:35
文章: 409
來自: Hong Kong
Hi All,
Did any big brothers knows how to alignment the Distagon 35mm/1,4 lens ? Since it has a floating elements as well as a focusing group moves together while focus. Many thanks.
:lol:

有谁Contax大哥知道Distagon 35mm/1,4 镜


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文章發表於 : 週一 15 12月 03 14:52:43 
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註冊時間: 週六 08 11月 03 01:36:09
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你想拆鏡 :wink: :wink:


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文章發表於 : 週四 18 12月 03 09:51:44 
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註冊時間: 週一 08 12月 03 13:46:35
文章: 409
來自: Hong Kong
After a while studying the construction of this lens, I know how to alignment for the focus and floating elements movements now. I am now test shoot some pictures to see my evaluation method works or not :lol: . The reasons why I need to re-alignment for this Distagon is I bought this lens in second hand market and at a relatively low price (Around a used 2.8 version's price). The seller mention that this lens is not sharp at all after the lens has been brings to service. The glass and body are very new, over 90% but only is not sharp at 1,4-2,8 aperture range. The corners are all burred at 1,4. That why selling it. Based on the fact and user reports that this 35mm/1.4 Carl Zeiss lens should not be that poor performed, therefore, I guess that this must be the Flaoting Elements alignments problem, which I have experienced before with my Nikon 35/1.4 Ais. Therefore I buy it and now attemp to do re-alignments. Hope my move is right LA :? If any Big Brothers have any suggestions, feel free to publish . Many Thanks.


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文章發表於 : 週四 18 12月 03 09:59:46 
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註冊時間: 週六 08 11月 03 07:56:21
文章: 5762
As long as you can get it at such a low price, you should consider to send it to CZ japan for an overhaul. I suppose it is not possible for anyone to calibrate the lenses from Carl Zeiss up to the factory standards in which you don't have the proper tooling, MTF measurement instrument, and all the necessary parameters.

You can contact UOI in Kwun Tong for the CLA (Clean, Lubricate and Adjustment) and I suppose the cost will be around $1500-2000 (w/o replacement of elements) and it takes 3-4 weeks to do so.

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文章發表於 : 週四 18 12月 03 17:48:39 
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註冊時間: 週一 08 12月 03 13:46:35
文章: 409
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Mine is West Germany version :(
Seems it is more expensive for calibration in Zeiss Germany. I will dis-assemble and try myself first :D
I hope I can success :lol:


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文章發表於 : 週四 18 12月 03 23:01:44 
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註冊時間: 週六 08 11月 03 07:56:21
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Yashica fans 寫:
Mine is West Germany version :(
Seems it is more expensive for calibration in Zeiss Germany. I will dis-assemble and try myself first :D
I hope I can success :lol:


In fact I just had my Distagon 35/1.4 AEG calibrated from CZ Japan............It took about 4 weeks for the overhaul.

I will try to take some photos to see if there are any difference....

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文章發表於 : 週五 19 12月 03 08:45:07 
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註冊時間: 週一 08 12月 03 13:46:35
文章: 409
來自: Hong Kong
Thanks Wah, I will wait for your good news. In the mean time, I am now making use of some digital image processing techniques for determine the optimum focus and floating elements alignments. I will test to see how well it works. Thanks again :D


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文章發表於 : 週五 19 12月 03 10:44:21 
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註冊時間: 週六 08 11月 03 07:56:21
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Yashica fans 寫:
Thanks Wah, I will wait for your good news. In the mean time, I am now making use of some digital image processing techniques for determine the optimum focus and floating elements alignments. I will test to see how well it works. Thanks again :D


wow..........you intend to capture the image and then analyse by DSP technique? :shock:

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文章發表於 : 週五 19 12月 03 11:52:30 
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註冊時間: 週一 08 12月 03 13:46:35
文章: 409
來自: Hong Kong
wah 寫:

wow..........you intend to capture the image and then analyse by DSP technique? :shock:


Yes AH ...not intend, but actually done LA. I use a CCD from a digital camera to for capture the image formed through the 35mm/1.4 Distagon and then by using "edge filter" in the spatial domain to extract the information content of the image. A sharply focused image has the hightest number of edges (similar concept as the contrast transfer function, mtf ). Apply the vertical and then a horizontal 3X3 spatial filter and you can get the edges of the image. It sounds difficult than it is in actually practice. Ofcourse, all the imaging processing is done in a workstation or PC (PC is really very powerful nowadays) :wink: FYI, a kind of 3X3 spatial edge extract filter is shown:
[ 0 0 0] [0 1 0]
[1 1 1] [0 1 0]
[0 0 0] [0 1 0]


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