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Himself
Joined: 01 Mar 2007 Posts: 3209 Location: Montreal
Expire: 2013-05-30
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Posted: Tue Mar 31, 2020 5:01 pm Post subject: Nikon 300/2.8 Ai-s stuck diaphragm |
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Himself wrote:
Last year I acquired a Nikon 300/2.8 Ai-s with a stuck diaphragm. Wide open.
I can see a small spring with a bolt hanging down there.
I tried to open it up from the mount but after I removed the mount I stopped because I didn't see any possibility to go further.
Anyone with some experience in dismantling one of those? I know it's far fetched but I had to ask.
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cooltouch
Joined: 15 Jan 2009 Posts: 9097 Location: Houston, Texas
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Posted: Tue Mar 31, 2020 9:56 pm Post subject: |
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cooltouch wrote:
This lens has internal focusing, right?
I was told some years ago, after buying a Canon 400mm with IF and inquiring about getting into the interior to remove some light fungus, that trying to get into any section of the lens in which the IF system was employed would destroy its calibration, requiring special gear to recalibrate the lens. So, I dropped the idea and just chose to live with the few spiderwebs of fungus.
So, that's the short answer. These lenses -- and I'm assuming that Nikon employs a similar mechanism -- require special equipment to dial in the focus during assembly and if you manage to dismantle any of these areas you will have disabled the lens's ability to focus at all. So, my recommendation is that you leave this repair to the professionals. It's a valuable enough lens where the cost of the repair will be worth it, I'm thinking.
On the other hand, if your 300/2.8 is NOT IF, well . . . I dunno. I would have followed your steps and approached from the rear, since that's where the aperture linkage ends up. _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
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visualopsins
Joined: 05 Mar 2009 Posts: 10463 Location: California
Expire: 2021-06-22
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Posted: Tue Mar 31, 2020 10:06 pm Post subject: |
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visualopsins wrote:
Screws under focus ring rubber? _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ 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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Himself
Joined: 01 Mar 2007 Posts: 3209 Location: Montreal
Expire: 2013-05-30
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Posted: Wed Apr 01, 2020 3:23 am Post subject: |
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Himself wrote:
Cooltouch - it is internal focus
Visualopsins - I'll look at it tomorrow.
Here is a link for the famous Nikon 300mm f/2.0 EDIF. I thought it was the same but I couldn't find the screws
http://www.company7.com/library/nikon/Nikon_0300f2.html _________________ Moderator Himself |
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Himself
Joined: 01 Mar 2007 Posts: 3209 Location: Montreal
Expire: 2013-05-30
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Posted: Wed Apr 01, 2020 6:16 pm Post subject: |
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Himself wrote:
I cannot remove the focusing ring.
Under it there is a port hole and through it I can access 2 screws.
But, I take Michael's word and I'll wait for the stores to open.
In the mean time I shoot wide open.
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cooltouch
Joined: 15 Jan 2009 Posts: 9097 Location: Houston, Texas
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Posted: Thu Apr 02, 2020 4:14 pm Post subject: |
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cooltouch wrote:
Yeah, that's what I'd do. Heck, it's most fun shooting a 300/2.8 wide open, anyway, isn't it? _________________ Michael
My Gear List: http://michaelmcbroom.com/photo/gear.html
My Gallery: http://michaelmcbroom.com/gallery3/index.php/
My Flickr Page: https://www.flickr.com/photos/11308754@N08/albums
My Music: https://soundcloud.com/michaelmcbroom/albums
My Blog: http://michaelmcbroom.com/blogistan/ |
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Himself
Joined: 01 Mar 2007 Posts: 3209 Location: Montreal
Expire: 2013-05-30
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Posted: Fri Apr 03, 2020 2:54 pm Post subject: |
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Himself wrote:
cooltouch wrote: |
Yeah, that's what I'd do. Heck, it's most fun shooting a 300/2.8 wide open, anyway, isn't it? |
Lots of light
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