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jhayashileite
Joined: 19 Sep 2018 Posts: 29 Location: São Paulo, Brasil
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Posted: Wed Sep 19, 2018 6:19 am Post subject: CZJ Biotar infinity focus problem |
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jhayashileite wrote:
Hello everyone
This is my first post as a member, after reading so many topics in this forum. Hope you guys can help me.
I have a Zeiss Biotar 58mm f2, silver 17-blade version with red T (SN 3112123). Formerly, it had an Exakta mount but it was replaced with a M42 screw mount. I bought it for really cheap and it was really dirty and quite frozen, due to the hardened grease inside its helicoid. It took a lot of force to make the focus and aperture rings to rotate. A friend of mine and I took the lens apart and cleaned it, removing the old grease and dirt from it, making the aperture and focus rings softer to move.
The problem I'm having is with the focus distances. This lens usually focuses from 0,9m to infinity, but mine only focuses to about 2m when the focus ring is set to infinity. I thought that it was still useful for some portraits, but the lens felt even more limited to use when I tested it, both in digital and in film. Since then, I didn't dare to disassemble the lens again, afraid of making it worse.
Hope you guys can help me with this. Thank you all. _________________ @hayashileite
24, São Paulo, Brasil |
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visualopsins
Joined: 05 Mar 2009 Posts: 10463 Location: California
Expire: 2021-06-22
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Posted: Wed Sep 19, 2018 3:14 pm Post subject: |
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visualopsins wrote:
Welcome jhayashileite
Intuition says the focus helical was not started on the correct thread; helicals are not a single thread but have multiple starting points. You may need to try each before finding correct thread which allows infinity focus. _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ like attracts like! ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮
Cameras: Sony A7Rii, Spotmatics II, F, and ESII, Nikon P4
M42 Asahi Optical Co., Lenses:
Takumar 1:4 f=35mm, 1:2 f=58mm (Sonnar), 1:2.4 f=58mm (Heliar), 1:2.2 f=55mm (Gaussian), 1:2.8 f=105mm (Model I), 1:2.8/105 (Model II), 1:5.6/200
Tele-Takumar 1:5.6/200, 1:6.3/300
Macro-Takumar 1:4/50
Auto-Takumar 1:2.3 f=35, 1:1.8 f=55mm, 1:2.2 f=55mm
Super-TAKUMAR 1:3.5/28 (fat), 1:2/35 (Fat), 1:1.4/50 (8-element),
Super-Multi-Coated Fisheye-TAKUMAR 1:4/17
Super-Multi-Coated TAKUMAR 1:4.5/20, 1:3.5/24, 1:3.5/28, 1:2/35, 1:3.5/35, 1:1.8/85, 1:1.9/85 1:2.8/105, 1:3.5/135, 1:2.5/135 (II), 1:4/150, 1:4/200, 1:4/300, 1:4.5/500
Super-Multi-Coated Macro-TAKUMAR 1:4/50, 1:4/100
Super-Multi-Coated Bellows-TAKUMAR 1:4/100
SMC TAKUMAR 1:1.4/50, 1:1.8/55
Other lenses:
Carl Zeiss Jena Flektogon 2.4/35
SMC PENTAX ZOOM 1:3.5 35~105mm, SMC PENTAX ZOOM 1:4 45~125mm
Nikon Micro-NIKKOR-P-C Auto 1:3.5 f=55mm, NIKKOR-P Auto 105mm f/2.5 Pre-AI (Sonnar), Micro-NIKKOR 105mm 1:4 AI, NIKKOR AI-S 35-135mm f/3,5-4,5
Tamron SP 17mm f/3.5 (51B), Tamron SP 17mm f/3.5 (51BB), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto
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Gardener
Joined: 22 Sep 2013 Posts: 950 Location: USA
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Posted: Wed Sep 19, 2018 3:59 pm Post subject: |
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Gardener wrote:
Unfortunately it will have to be taken apart. You did not assemble it correctly - a typical rookie mistake, helicoid was not started at the right point. |
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Sciolist
Joined: 29 Mar 2017 Posts: 1445 Location: Scotland
Expire: 2021-04-16
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Posted: Wed Sep 19, 2018 4:27 pm Post subject: |
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Sciolist wrote:
Hi,
You may find this thread helpful if your lens is similar.
http://forum.mflenses.com/stiff-focusing-ring-on-a-biotar-58-2-no-problem-t24157.html |
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jhayashileite
Joined: 19 Sep 2018 Posts: 29 Location: São Paulo, Brasil
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Posted: Wed Sep 19, 2018 5:43 pm Post subject: |
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jhayashileite wrote:
Thanks a lot for the replies, guys. I will work on it as soon as I can. Have a nice week. _________________ @hayashileite
24, São Paulo, Brasil |
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jhayashileite
Joined: 19 Sep 2018 Posts: 29 Location: São Paulo, Brasil
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Posted: Sat Sep 22, 2018 11:56 pm Post subject: |
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jhayashileite wrote:
Quick update:
I was able to disassemble the lens and bring back infinity focus, but my problem now is screwing the rings back together. The screws that I still have on the lens are almost unusable, being old and worn off, specially after my attempts to fix the lens.
I would like to know if there are any ways to replace those screws or other way to but the rings back in place. It already works properly, but my Biotar has some inside threads exposed to dust (and is looking like an Industar 61).
Any help will surely be appreciated. _________________ @hayashileite
24, São Paulo, Brasil |
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