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tak_61
Joined: 24 Sep 2011
Posts: 3
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 Posted: Sat Sep 24, 2011 3:44 pm Post subject: Blocked focus on a Biometar 80mm 2.8 for pentacon six |
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tak_61 wrote:
Dear all,
it happend to me to have a Biometar 80mm with a beautiful glass (no scratches, no fungus no cleaning marks) but unfortunately the focus ring moves only for 20- 25 degrees from infinty and than it becames hard and does not move any further. The lens was not very expensive so I decided to open it. A clue on a possible cause of the defect is the strong blow that bend the outer zebrated alluminium barrel
The other side of the body looks like this
If i try to unscrew moving the inner ring with the two "ears" it moves just a bit and then it stucks. I tried to remove the two brakets which hold the two "ears" and doing so the outer ring ( the one with the numbers of meters ) moves but the internal part does not. Maybe there is some retaining screw hidden somewhere? Or the blow coud have deformed the helicoid (I hope not!). Coud somebody be so kind to explain me how to unsrew the helicoid?And/or have an idea on what is that is preventing the focus ring to do its job? Thanks a lot! |
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Spotmatic
Joined: 18 Aug 2008
Posts: 4045
Location: Netherlands
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| Posted: Sat Sep 24, 2011 4:46 pm Post subject: Re: Blocked focus on a Biometar 80mm 2.8 for pentacon six |
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Spotmatic wrote:
Welcome to the forum! Please let me quote your message; a new user's first post can never contain pictures.
| tak_61 wrote: |
Dear all,
it happend to me to have a Biometar 80mm with a beautiful glass (no scratches, no fungus no cleaning marks) but unfortunately the focus ring moves only for 20- 25 degrees from infinty and than it becames hard and does not move any further. The lens was not very expensive so I decided to open it. A clue on a possible cause of the defect is the strong blow that bend the outer zebrated alluminium barrel
The other side of the body looks like this
If i try to unscrew moving the inner ring with the two "ears" it moves just a bit and then it stucks. I tried to remove the two brakets which hold the two "ears" and doing so the outer ring ( the one with the numbers of meters ) moves but the internal part does not. Maybe there is some retaining screw hidden somewhere? Or the blow coud have deformed the helicoid (I hope not!). Coud somebody be so kind to explain me how to unsrew the helicoid?And/or have an idea on what is that is preventing the focus ring to do its job? Thanks a lot! |
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Peter - Moderator
Pentax K-5 + Pentax 645 + Canon 5D + Bessa RF 10,5cm Heliar, and a 'little' bag full of MF lenses. The lens list is * here *.
My fast 80s: Asahi-Kogaku Takumar 83mm f/1.9 - Super-Takumar 85mm f/1.9 - FA 77mm f/1.8 Limited - Cyclop 85/1.5 (Helios-40 innards) - Komura 80mm f/1.8 - Meyer Görlitz Primoplan 7,5cm 1:1.9 - Carl Zeiss Jena 80mm f/1.8 Pancolar - Canon 85mm f/1.8 S.S.C. - Canon 85mm f/1.2 S.S.C. Aspherical |
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WolverineX
Joined: 19 Apr 2009
Posts: 1693
Location: Zagreb , Croatia , Europe
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| Posted: Sat Sep 24, 2011 6:05 pm Post subject: |
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WolverineX wrote:
here is the thread on how to dismantle the biometar lens
http://forum.mflenses.com/how-to-dismantle-an-atomic-bomb-biometar-80mm-p6-t30679.html
_________________
my tools:Oly E-M5 + 45mm/1.8 + Oly E-520 + 12-60 + 14-42 + 70-300 + Sigma 105mm + FL-50R + EC20 + SRF-11 ring flash
http://forum.mflenses.com/wolverinex-testing-my-lenses-series-link-list-t39524.html |
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tak_61
Joined: 24 Sep 2011
Posts: 3
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| Posted: Sat Sep 24, 2011 7:43 pm Post subject: |
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tak_61 wrote:
First of all thanks for the kind wellcome in this exciting forum!
Thank for the interesting link. Following your clear procedure I thing I get to the point where I need to dismantle the "inner core" of the "bomb"! But I would like not to cause more damage than good. So I need some help from more "senior" people. Thanks again |
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Kathmandu
Joined: 09 Dec 2009
Posts: 1479
Location: (Kathmandu,Nepal. Currently)Pacific Northwest, USA
Expire: 2012-04-08
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| Posted: Sat Sep 24, 2011 9:11 pm Post subject: |
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Kathmandu wrote:
Could you post a larger version of your first picture(the one with the zebra markings) in the inset .
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kathmandu
Sony α 700 DSLR
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tak_61
Joined: 24 Sep 2011
Posts: 3
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| Posted: Sun Sep 25, 2011 8:07 am Post subject: |
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tak_61 wrote:
| Kathmandu wrote: |
| Could you post a larger version of your first picture(the one with the zebra markings) in the inset . |
sory for the low quality, but they have been taken with an Autofocus lens(....)
The bent alluminium does not touch the moving inner part, at least at the external edge, I have somne doubt on the internal hidden parts.
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