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Author Topic: Cleaning Nikon 24mm f2.8 AI aperture leaves  (Read 6866 times)

Zang

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Cleaning Nikon 24mm f2.8 AI aperture leaves
« on: May 05, 2019, 22:18:07 »
Hello all,

I am disassembling Nikon 24mm f2.8 AI and want to get to the aperture. I was able to separate the objective assembly and can easily separate the rear element from the inner helicoid (please check the picture below). Now I get stuck on how to get to the aperture. Does any one know? Would greatly appreciate your inputs!

Cheers,
Zang
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Roland Vink

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #1 on: May 06, 2019, 01:31:33 »
Richard Haw does not (yet) have anything specific to the AI 24/2.8 but his lens repair articles should help:
https://richardhaw.com/lens-repair-articles/

Note that the AI 24/2.4 has floating elements (close range correction) which mean there are two sets of focus helicoids, one for the front group and one for the rear elements, so this lens lens is more complicated to repair than simpler lenses.
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #2 on: May 06, 2019, 17:53:58 »
Thanks Roland. Rick's block was the first thing I started with. Also, I have passed the double helicoid stage and now dealing with the objective block alone. It seems getting to the aperture may require taking the objective apart. Will update here if I found it out.
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Jack Dahlgren

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #3 on: May 06, 2019, 19:45:13 »
Quote from: Zang on May 05, 2019, 22:18:07
Hello all,

I am disassembling Nikon 24mm f2.8 AI and want to get to the aperture. I was able to separate the objective assembly and can easily separate the rear element from the inner helicoid (please check the picture below). Now I get stuck on how to get to the aperture. Does any one know? Would greatly appreciate your inputs!

Cheers,
Zang


Looks like if you remove that set screw you should be able to unscrew the front element. Mark before disassembling!
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #4 on: May 06, 2019, 21:22:20 »
Quote from: Jack Dahlgren on May 06, 2019, 19:45:13

Looks like if you remove that set screw you should be able to unscrew the front element. Mark before disassembling!

No, that's the focusing guide, removing it will be disaster :-P
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Jack Dahlgren

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #5 on: May 07, 2019, 02:26:52 »
Quote from: Zang on May 06, 2019, 21:22:20
No, that's the focusing guide, removing it will be disaster :-P

I'm thinking the screw marked in red.
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #6 on: May 07, 2019, 04:17:57 »
Quote from: Jack Dahlgren on May 07, 2019, 02:26:52
I'm thinking the screw marked in red.

Oh no, there is no screw there.
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Erik Lund

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #7 on: May 07, 2019, 12:17:59 »
Basically same as this one:


https://richardhaw.com/2017/11/04/repair-nikkor-n-24mm-f2-8-auto/


Richard has documented these very well!


BTW aperture blades ;) not leaves,,, could be why you didn't find it :)

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Erik Lund

Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #8 on: May 07, 2019, 13:18:39 »
Quote from: Erik Lund on May 07, 2019, 12:17:59
Basically same as this one:


https://richardhaw.com/2017/11/04/repair-nikkor-n-24mm-f2-8-auto/


Richard has documented these very well!


BTW aperture blades ;) not leaves,,, could be why you didn't find it :)

Thanks Erik, I also have read this. There is nothing about servicing aperture blades. Also, I googled all possible English name combination :)
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Jack Dahlgren

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #9 on: May 07, 2019, 18:19:54 »
Quote from: Zang on May 07, 2019, 13:18:39
Thanks Erik, I also have read this. There is nothing about servicing aperture blades. Also, I googled all possible English name combination :)
Did you get it apart?
Should look like this:
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #10 on: May 07, 2019, 19:01:09 »
Quote from: Jack Dahlgren on May 07, 2019, 18:19:54
Did you get it apart?
Should look like this:

Hey Jack, I have passed this too. Still do not see the aperture. I just stop here to take time for more research. I am not sure if I can take apart the block shell without disassembling each element. They are really hard to disassemble and I do not want to risk, unless necessary.
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Jack Dahlgren

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #11 on: May 08, 2019, 04:34:52 »
Quote from: Zang on May 07, 2019, 19:01:09
Hey Jack, I have passed this too. Still do not see the aperture. I just stop here to take time for more research. I am not sure if I can take apart the block shell without disassembling each element. They are really hard to disassemble and I do not want to risk, unless necessary.

Not sure what you mean about not seeing the aperture. It should be between front objective and rear. Maybe it is wide open? Take a photo looking down the center from both ends.
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richardHaw

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #12 on: May 08, 2019, 04:57:06 »
pictures of my hands are all over the internet. people can hire fortune tellers and predict my future  :o :o :o

i wouldnt advise working on this lens if you are a novice. the iris can be adjusted and that is dangerous if you dont know how to put it back again ::)
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #13 on: May 08, 2019, 05:13:58 »
Quote from: Jack Dahlgren on May 08, 2019, 04:34:52
Not sure what you mean about not seeing the aperture. It should be between front objective and rear. Maybe it is wide open? Take a photo looking down the center from both ends.

Hey Jack, by not seeing the aperture I mean it is still behind the glasses. I think I figured out the way to get into it. Will update later.
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Zang

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Re: Cleaning Nikon 24mm f2.8 AI aperture leaves
« Reply #14 on: May 08, 2019, 05:16:40 »
Quote from: richardHaw on May 08, 2019, 04:57:06
pictures of my hands are all over the internet. people can hire fortune tellers and predict my future  :o :o :o

i wouldnt advise working on this lens if you are a novice. the iris can be adjusted and that is dangerous if you dont know how to put it back again ::)

Hey Rick... wise advice as I am a novice+inappropriate tools, but it is too late :) In the worst case I am one lens less :)
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