Wobble Nikkor :)

[Zang]

Hi all,

I have bought an used Nikkor 35mm F2.8 AIS. The lens looks fresh optically and visually. Focusing is smooth but too easy. However, the focus ring and the internal objective are loose. I can grab the front element housing and move it up and down or wiggle it left and right with small movement. If I shake the lens, I can also hear the sound of the wiggling parts. There is no signs of damage or previous disassembly attempts.

Have you guys seen this issue? What is the cause and does it require fixing?

Cheers,
Zang

[pluton]

My gueass: loose screws inside.  Maybe Richard Haw can help:https://richardhaw.com/2018/12/23/repair-nikkor-35mm-f-2-8-ai-s/

[Zang]

I decided to overhaul this lens It turned out the helicoids are loose after the grease dried out. Regreased it and everything works smooth now. I am disappointed with Nikon's precision in this lens, though.

A side note, I failed to mark the separation points of the helicoids and it took be a bit to figure out where they were

[simsurace]

Congratulations on the repair!

A side note, I failed to mark the separation points of the helicoids and it took be a bit to figure out where they were

Been there . Luckily you did not make this mistake with the 35/1.4 Ai-s!

[Zang]

Ha... I have pretty good pictural memory so it cost me 3 attempts (of putting together the helicoids, not the whole lens) to make the relative positions of the element match my memory. Then I reassemble the whole lens and everything turned to be perfect. I was more careful with 24mm f2.8 but that lens was hell to work with, not because of the complexity but the stubborn screws that I stripped a few.

[simsurace]

Richard Haw has a lot of good tips for working with screws, I'm sure you've read them. As for the helicoids: if the lens is unit focusing the position can be worked out, if laboriously, but I would not know how to verify that the helicoids of a lens with CRC have been reassembled correctly. I recently came across a 35/1.4 which had been assembled incorrectly, the infinity focus was off but the lens did not perform well at any distance. I had to consult a qualified repairman who knew how to restore it to specs.