Aperture lever 180mm/f2.8 AiS

[John Geerts]

I have here a nice sample of the 180mm/2.8  Ais, early serialnumber,  with a problem.

The aperture and aperture ring is working fine, the blades are crystal clear. But the small lever is somehow stuck. It is hard to move, and is obviously not connected to the blades as it should be. This results in exposure problems in camera when the lens is not used wide open (over-exposure). Also the focussing is not as smooth as it should be, but that  may be a question of extra usage, as the lens was stored for more than 10 years. 

Is such a thing easy to repair or fix? 

[Bjørn Rørslett]

Hm. The first thing to look for is a lever bent out of shape. The sideways clearance is not large. Check if the lever sticks right up perfectly normal to the mounting surface of the bayonet.

If this isn't the case, bring some pressure to set it straight.

Next step is removing the bayonet and look for troubles inside. You are now moving in perilously close to Dr. Lens Territory, though.

[John Geerts]

Thanks Bjørn.   Looks I am in trouble. The lever only sticks right at F/32 and bends to it's position at F/2,8,  Furthermore when focus at infinite, and rear element to it's most outward position, it's very hard to have a movement at all. 

Shall have to find some tools for bayonet-removal and pray it will be easy when opening up 

[Erik Lund]

Did you take it apart at some point?

The aperture lever arm on this one goes deep into the lens,,,

F-mount comes apart as normal but to get it off the lens a bit of fiddling and the lens at minimum distance and all at f/5.6 as i recall,,,

To put it together same in reverse

[Bjørn Rørslett]

****** NB **********

N E V E R   T R Y  T O   R E M O V E   B A Y O N E T   S C R E W S  W I T H O U T   J I S   S C R E W D R I V E R S

I cannot stress this point enough.

[Erik Lund]

And a stable table to work on,,,

[stenrasmussen]

I'm inclined to think the bayonet has been off before and put back in an erraneous manner. The aperture blade mechanism link is misaligned.

[John Geerts]

I haven't opened it yet, want to be sure what I am doing.

I think you are right, Sten, looking at the screws. Probably not done by a JIS one...

[Bjørn Rørslett]

As Erik mentioned, the internal aperture lever is long and easily put wrongly so as to block normal operation.

When you assemble the bits and pieces and the aperture lever is sunk into the lens innards, check that the position is correct by rotating the aperture ring and see the aperture blades follow. Then move the lever sideways to see that the aperture fully opens and immediately snaps back when you release the lever.

[Øivind Tøien]

Also if you have the mount off, check that the bearings in the mount (if present in this design) are moving freely. I have in the past encountered a case where the locking ring for the bearings screwed itself tighter due inadequate red sealant to lock it in place. Just re-positioning it and resealing solved the problem of an aperture lever that did not move freely.

[John Geerts]

Thanks for all the advice. Will first look for the proper JIS - tools.

[John Geerts]

One of the screws appeared to be stuck. A bit tricky to go any further, contacted the seller and returned the lens.

[John Geerts]

Epilogue.

With JIS-tools in the hand, I decided to clean a long forgotten lens, the Nikkor 35/2 Ai, which was isolated in a sunny spot as the inner lens showed funghi-contamination.

Appeared to be very easy, screwing off (Three screws) the bajonet and  the back part of the lens. Followed by a succesfull cleaning.  Putting all back gave some problems, but thanks to Roland Vink's excellent website as an example,  it all fits again.
Details of the Nikkor 35/f/2

Only a small question, can there be a mis-alignment regarding reaching infinity?


After the cleaning...