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tikkathree
Joined: 19 Jun 2010
Posts: 755
Location: Lovely Suffolk in Great Britain
Expire: 2012-12-28
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 Posted: Mon Aug 13, 2012 6:25 am Post subject: Mamiya FC lens (for Prismat) seized focus - anyone? |
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tikkathree wrote:
I just won (?) on EBay a nice Mamiya Prismat CPH with the 50mm and 100mm lenses. Actually I already have one prismat so it was for the 100mm lens that I chased after it.
On delivery I find that the lens is seuzed rock solid at infinity.
I've emailed the vendor and am waiting to discuss his misdescription and it could well be that it all goes back. If he'll adjust the price I'm faced with either a fixed infinity focus lens or having a little go myself to see what's occuring inside.
In the meantime I'm thinking about the logistics of opening up the lens to see what repairs are needed but I have never stripped a lens before so don't know if I have the time or tools to complete the job.
Here's what she looks like:
_________________
I used to think digital was fun but then I discovered film, then I found old lenses and then, eventually I found rangefinders.
EOS 5DII, loadsalenses
Canon G9 IR conv,
MF: TLR, 645 and folders
35mm: Oly OM Pro bodies 1, 2, 3 and 4; Soviet RF kit |
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tikkathree
Joined: 19 Jun 2010
Posts: 755
Location: Lovely Suffolk in Great Britain
Expire: 2012-12-28
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| Posted: Thu Aug 16, 2012 6:01 pm Post subject: |
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tikkathree wrote:
Now that I own this lens at a much reduced price I need to find my way in: anyone opened one of these before please?
_________________
I used to think digital was fun but then I discovered film, then I found old lenses and then, eventually I found rangefinders.
EOS 5DII, loadsalenses
Canon G9 IR conv,
MF: TLR, 645 and folders
35mm: Oly OM Pro bodies 1, 2, 3 and 4; Soviet RF kit |
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ljherrero
Joined: 25 Jun 2014
Posts: 30
Location: Madrid (España)
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| Posted: Mon Dec 19, 2022 1:27 pm Post subject: |
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ljherrero wrote:
| tikkathree wrote: |
| Now that I own this lens at a much reduced price I need to find my way in: anyone opened one of these before please? |
Hi,
I understand that a lot of time has passed (more than 10 years) but since I am faced with exactly the same problem (a Mamiya-Sekor F.C. 3.5/100 with the focus ring stuck, in my case between the 20m and infinity marks) and I found this entry looking for some information about the Mamiya Prismat (quite scarce) which is why I would appreciate it if you told me if you solved the problem and how; I disassembled the front optical group to clean some fungus that it had, but removing some screws from the focusing ring I have not come to know how to move forward to unclog it.
By the way, I got a Prismat CPH for scrap with the idea of making an adapter (although I also lack the information about the flange distance of the Prismat PH system https://www.photo.net/forums/topic/537258-flange-distance-of-mamiya-prismat-ph-and-cph/#comment-5761072)
All the best. |
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visualopsins
Joined: 05 Mar 2009
Posts: 11011
Location: California
Expire: 2025-04-11
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| Posted: Mon Dec 19, 2022 5:46 pm Post subject: |
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visualopsins wrote:
Enter through name ring removal perhaps?
_________________
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Cameras: Sony ILCE-7RM2, Spotmatics II, F, and ESII, Nikon P4
Lenses:
M42 Asahi Optical Co., 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
M42 Carl Zeiss Jena Flektogon 2.4/35
Contax Carl Zeiss Vario-Sonnar T* 28-70mm F3.5-4.5
Pentax K-mount SMC PENTAX-A 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 (151B), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto (Kiron)
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ljherrero
Joined: 25 Jun 2014
Posts: 30
Location: Madrid (España)
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| Posted: Mon Dec 19, 2022 7:36 pm Post subject: |
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ljherrero wrote:
Unscrewing the front from the labeled ring only removes the optical group before the diaphragm (this is how I cleaned one of the elements affected by fungus), but the focusing helicoid is not accessed. |
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ljherrero
Joined: 25 Jun 2014
Posts: 30
Location: Madrid (España)
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| Posted: Tue Dec 20, 2022 4:20 pm Post subject: |
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ljherrero wrote:
...another one of the Prismat PH lenses that I just received (Mamiya Sekor F.C. 1.9/48mm.) has exactly the same thing; the lever that controls the iris works, but the distance adjustment ring remains locked until absolutely immobile (this time between the 1.5m and 2m mark); I'm beginning to think that these lenses have some special trick to move the focus (or suffer from the same problem, like the green grease on the helicoids of Agfa bellows cameras) |
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