Author Topic: Nikkor 300mm f4 disassembly need help  (Read 4238 times)

keyojimbo

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Nikkor 300mm f4 disassembly need help
« on: October 21, 2020, 19:58:28 »
Searched a lot online with practically zero results. best I can find is a single image on facebook of the front and mid groups out of the body

I can see the three set screws under the lens hood around the front group, and 3 larger screws behind the front group looking down the barrel. removing the set screws under the hood doesn't appear to loosen anything. but can't figure out how to get the front group out of the barrel. the retainer ring lets me access the front element, then another retainer ring the 2nd element in the front group. the third element doesn't seem to have any retainer ring, probably on the other side but can't be accessed without removing the whole front group. I'm not seeing a way to getting the front group out to access the 3 screws that holds front section of the barrel to the lower lower half at the focusing ring. No notches or holes for spanners that I can see for the front group assembly.

any pointers greatly appreciated.


Erik Lund

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Re: Nikkor 300mm f4 disassembly need help
« Reply #1 on: October 27, 2020, 11:17:14 »
Set screws sometimes needs complete removal, since they sometimes lock rotation, like for a big thread, also solvent can be dripped in when they are removed to release things.Good luck!
Erik Lund

Erik Lund

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Re: Nikkor 300mm f4 disassembly need help
« Reply #2 on: October 27, 2020, 11:18:34 »
Set screws sometimes needs complete removal, since they sometimes lock rotation, like for a big thread, also solvent can be dripped in when they are removed to release things.Good luck!
BTW check out Ricks page;

https://richardhaw.com/lens-repair-articles/

Here are similar lenses ;)
Erik Lund

keyojimbo

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Re: Nikkor 300mm f4 disassembly need help
« Reply #3 on: October 30, 2020, 02:18:48 »
Thanks for reply. Yep I regularly visit Richard's blog as well as mikeno62 youtube channel.

Turns out the inner tube that sticks out above the retracted lens hood is the front group cell, and I managed to losen it with a soft rubber pad after removing the set screws under the lens hood. that was enough to  get me past the middle group and clean out some sizeable dust specks trapped between the rear and middle group. good enough!

Next one I'm still trying to figure out is Nikkor 300mm f4.5 AI-S ED IF. But I need to take some photos first.

Erik Lund

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Re: Nikkor 300mm f4 disassembly need help
« Reply #4 on: October 31, 2020, 00:07:20 »
That’s great, hope you get it together nicely!
Erik Lund

Ezio

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Re: Nikkor 300mm f4 disassembly need help
« Reply #5 on: April 23, 2022, 17:06:28 »
Hi, I found this post because I have the same problem. I bought an old lens. It looks very worn :-)
He has sand inside and the focus ring is noisy. I have disassembled the front and back, but I cannot extract the lenses in the central body where the focusing system is.

I think I should remove the focus ring (where I removed the rubber) from the ring just behind. I removed the three small screws, but I can't unscrew the ring despite the presence of the two grooves. By the way: the two grooves are not at 180 ° ... strange.
I fear that the two grooves are not original, but made from a previous attempt at reopening

Can you help me? Thanks
Ezio


Erik Lund

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Re: Nikkor 300mm f4 disassembly need help
« Reply #6 on: June 28, 2022, 09:50:23 »
I believe this is your next step:

Turns out the inner tube that sticks out above the retracted lens hood is the front group cell, and I managed to losen it with a soft rubber pad after removing the set screws under the lens hood. that was enough to  get me past the middle group
Erik Lund

Ezio

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Re: Nikkor 300mm f4 disassembly need help
« Reply #7 on: February 22, 2023, 08:14:59 »
Hi, I tried again, with your system I disassembled the front lens, but not the central lenses.
Does it just unscrew? Do I have to use a special rubber cone to disassemble the lenses?
Thanks for your help
Ezio