Monkeyfinger
Joined: 04 Nov 2024 Posts: 1
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Posted: Mon Nov 04, 2024 6:51 am Post subject: Stuck cleaning Yashinon-DX f/2 50mm - SOLVED! |
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Monkeyfinger wrote:
[edit] I got it loose! And eradicated the fungus!
Dripping acetone on the edge of the screw thread and heating up the metal with hot air caused a capillary action for the acetone to creep in between the screw thread, and the retainer cone screwed right off.
After that I cleaned the glass with 50% white vinegar and 50% water, which destroyed the fungus faster than GAS destroys my wallet.
Extra bonus, I can't see any damage traces from the fungus.
---- Original thread: ----
Hey everyone,
I'm disassembling the front element group of a Yashica Yashinon-DX f/2 50mm lens, the all-black M42 version without any chrome parts or accents. I’m trying to remove a starting fungal infection growing behind the front element but have hit a roadblock and could really use some help.
I easily removed the entire front element group from the lens body, but can’t seem to open the front element group itself. This version of the Yashinon-DX seems to have a different mounting system than most other Yashinon-DX lenses. It was probably produced around 1972–1974 at the end of the Yashinon-DX era, just before the Yashica ML lenses came out. Which could explain it's more modern mounting design.
What I Have Tried:
- Wiggling/pulling the retainer cone (the stepped cone on top) upward.
- Turning the retainer cone (mostly counterclockwise) to check if it’s threaded.
- Trying to use a lens spanner on the notches in the retainer ring below, but the cone is too wide to fit a spanner in.
- Twisting the bottom part of the enclosure.
- Adding a tiny amount of Moebius 8000 oil and later silicone spray at the bottom edge of the retainer cone to help loosen it.
- Carefully warming up the enclosure with a hot air space heater to loosen any adhesive or thread locker.
I don't know what the correct method of disassembly is, so I’ve been careful not to apply too much force.
My Questions:
1. Has anyone here disassembled this version of the Yashinon-DX f/2 50mm?
2. Or has anyone worked on a lens with a similar front group design?
3. Does anyone know if the retainer cone is threaded, press-fitted, or held another way?
4. Are there other steps I should try?
Here is a link to photos for clarity:
https://imgur.com/a/JfXUhBX |
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visualopsins
Joined: 05 Mar 2009 Posts: 11097 Location: California
Expire: 2025-04-11
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Posted: Sat Nov 09, 2024 4:47 am Post subject: |
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visualopsins wrote:
Welcome Monkeyfinger! Happy you got it sorted. Thanks for sharing with us here. _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ like attracts like! ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮
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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