Squeaky 35mm f/1.4 AIS

[charlie]

My 35mm f/1.4 lens squeaks and vibrates a bit when turning the focus ring, sounds and feels like the grease has dried up.
I'm curious if any one can tell me how difficult of a job it would be to re-grease this particular lens myself.

[Bjørn Rørslett]

Erik the Great Dane will certainly know. Ask him.

[Erik Lund]

Fairly difficult as it is a CRC lens. It has a rear section of lens elements that has its own focusing helicoil.
So take very good care when taking it apart. Mark all parts as you take it apart.

[charlie]

Erik, thank you for the insight. Perhaps I will just take this to someone that already has the tools and experience.

[Erik Lund]

I think that is a good idear

[David H. Hartman]

I had a lens and probably still have it that squeaked when focused. I removed the bayonet and inspected the "fork" that moves the aperture deep in the lens. It was rough so I polished it a touch with  No. 600 wet/dry sandpaper and then lubricated the edges minutely. I spread a tiny dot of lub on my index finger, spread it [ultra] thin and transferred the lub to the fork. I reassembled the lens and it has never squeaked since. The lens might have been my 85/2.0 Ais.

Dave

[richardHaw]

squeaking is caused by a couple of factors:

1. as mentioned, lack of lubrication on the forks
2. unlubricated helicoid keys
3. helicoid key screwed too tight
4. a screw hitting something
5. warped barrel (ding,dropped) so parts of it is hitting something
6. rarely dry helicoid
7. mouse inside the lens
8. wrong tolerances

if your lens wiggles a bit, it is a sign that the helicoid key was not properly seated or it may have gotten loose.
from the sound of your problem, it is also possible that the lens' adjustments for focusing have gone loose and a brass washer might be hitting something as you focus.

[charlie]

Thanks for your input.

The lens itself is visually in quite good shape, no dings, dents, or signs that it has been dropped or opened up.
I wouldn't say that the lens wiggles, it's not 100% wiggle free, but seems comparable to my other AI-s lenses.
I can say the the squeak is less apparent when the lens is pointing straight up or down and much more apparent if I there is weight on the end of the lens, like if a lens is reversed on it or it is part of a relay, but that's not surprising.

Because of what Erik said, it being a CRC lens makes it more complicated to take apart and lube I am hesitant to take it apart myself. Perhaps removing the bayonet to inspect the fork with out going further into it, as David mentioned, might be reasonable to try?

[richardHaw]

Thanks for your input.

The lens itself is visually in quite good shape, no dings, dents, or signs that it has been dropped or opened up.
I wouldn't say that the lens wiggles, it's not 100% wiggle free, but seems comparable to my other AI-s lenses.
I can say the the squeak is less apparent when the lens is pointing straight up or down and much more apparent if I there is weight on the end of the lens, like if a lens is reversed on it or it is part of a relay, but that's not surprising.

Because of what Erik said, it being a CRC lens makes it more complicated to take apart and lube I am hesitant to take it apart myself. Perhaps removing the bayonet to inspect the fork with out going further into it, as David mentioned, might be reasonable to try?

depends on which lens but from my humble experience, the CRC unit should come out together with the objective. so long as you do not disturb the tolerances then it should be OK. otherwise, take plenty of notes.
  if you are not comfortable with the idea then just let it be.

what you described sounds like uneven wear. probably cause is the lack of lubrication for the forks and more likely, the objective was not seated properly.

[David H. Hartman]

I think the aperture fork is supposed to be dry. To add more I think I used silicone grease by placing a tiny dot on my index finger and then spreading it ultra thin with my thumb. I only wanted to stop the chaffing. I polished the fork contact edges first with #600 wet/dry sandpaper. I was really light about it as I didn't want to add slop. If I had it I would have used #1000 or maybe #2000 sandpaper. The squeak was like a cricket rubbing its wing with its leg, the fork being the wing. I don't remember how I knew it was the fork but I was sure when I opened the lens. Perhaps the lens didn't squeak when the DoF preview button was pushed indicating that only one side of the fork caused the problem.

I'm still not sure of the lens but it was probably the 80/2.0 AIS. I softened the thread lock on the bayonet with a acetone. I believe the thread lock to be white, high temperature Loctite. A camera repairman friend uses a small portable butane soldering iron to heat the screw and thread lock.  It was a really easy fix.

Dave

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Can anyone confirm whether the aperture fork is normally lubed or not?

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I didn't want any lube to have a chance to migrate to the aperture blades. That was my thinking when I applied the lube so minutely.

[richardHaw]

Hi. the forks need to be lightly lubricated. what i do is i just wipe my brush for grease application until il is dryish and then wipe it on the fork's groove.
it does help specially for small lenses like the 50mm f/1.8 Ai-s pancake version