Nikon Lenses not stopping down

Peter De Smidt · May 21, 2007

I have two Nikon lenses that aren't stopping down, a 20mm AF and a 105 AIS. The lenses don't stop down even when I slid the black lever on the back of the lens. Is this something that can fixed?

Pinholemaster · May 21, 2007

Sorry. Any good camera repair shop can get the parts to put a new iris in your lenses.

What makes me wonder is why both lenses aren't stopping down. You might want to bring the camera in as well, just in case something in the camera is breaking the lenses.

John Koehrer · May 21, 2007

New parts are more than likely not needed.
Usually the reason the aperture doesn't move is that lube from the focusing helical has migrated to the housing & is causing the iris to stick to the housing.
The surface tension can't be over ridden from the really light spring used to stop the poor little thing down.
It's a simple(?) Cla to correct

Brac · May 21, 2007

John Koehrer said:
New parts are more than likely not needed.
Usually the reason the aperture doesn't move is that lube from the focusing helical has migrated to the housing & is causing the iris to stick to the housing.
The surface tension can't be over ridden from the really light spring used to stop the poor little thing down.
It's a simple(?) Cla to correct

That's been my experience too. I had it happen to a Pentax lens and a Vivitar. Both were rarely used and quite old and I think that was the root of the problem. At the time Vivitar had their UK HQ in the same town as me so I took it in. They put it right and didn't even charge though it was years and years past its guarantee expiry.

ccbob · May 21, 2007

I've had to return my 20/f2.8 back to Nikon three times already in the last 1.5 years for this exact problem. Each time they simply clean and re-lube it. It's been a real disappointment for me. But, I guess as long as it is covered by the 5 year warranty, I have one less thing to complain about.

Good luck.

Lynda · May 22, 2007

I have a Nikon 50/f1.4 that I have had fixed twice. I don't use that camera or lens much over the winter and this spring the thing is stuck wide open, again. Is this a problem with these lenses? Is my house too dry?
Lynda

Curt · May 22, 2007

Lack of use was the problem with mine.

Mike Kovacs · May 22, 2007

My opinion is that they are fixing the problem but not the cause. Next time, they need to disassemble the lens completely and replace the lubrication on the helical. This is the source of the oil that is migrating into your iris.

They should know this and coming from a repair background, I expect a lot more from Nikon.

ccbob said:
I've had to return my 20/f2.8 back to Nikon three times already in the last 1.5 years for this exact problem. Each time they simply clean and re-lube it. It's been a real disappointment for me. But, I guess as long as it is covered by the 5 year warranty, I have one less thing to complain about.

Good luck.

Peter De Smidt · May 23, 2007

Can anyone recommend a good place to get a Nikon lens CL'A'd?

John Koehrer · May 24, 2007

Mike Kovacs said:
My opinion is that they are fixing the problem but not the cause. Next time, they need to disassemble the lens completely and replace the lubrication on the helical. This is the source of the oil that is migrating into your iris.

They should know this and coming from a repair background, I expect a lot more from Nikon.

And like everything else today, anything you do to make the job go faster means more money in your pocket.
Cleaning out the diaphragm housing & avoiding cleaning & relubing the helical means that much less work(time) for the technician.
If the tech's on commission it means he can go on to the next piece that much more quickly. If the tech is an employee on an hourly rate Then management uses the same logic. Time is money, quit wasting my time(I can hear the whip cracking now).

Wendel4 · May 24, 2007

I had a Nikkor 28mm f/2.8 aperature gum up three times like that. I took it to two different shops for CLAs. The first shop only fixed it for 6 months, then the same problem. Shop #2's fix only lasted for about three months. I took it back, and he re-did the job, but again, much less than a year of use. The third time I just bought a replacement lens, as it was cheaper than infinate repair visits. BTW, it was the only lens I ever bought from abroad, so no US warranty.

Peter De Smidt · May 24, 2007

An issue is that KEH lists the same lens in bargain condition for $254, and a repair person quoted me a price of $120. The KEH lens is in better condition than mine, at least judging from the picture. If I was convinced that the repair person would do a good job, I'd go for the $120, but if it'll crap out in, say, under a year, I'd rather get the KEH. Thoughts?

John Koehrer · May 25, 2007

Does the repair also cleaning(thoroughly) the helical & relube?
The problem usually occurs when the lube breaks down through heat, vaporizes & condenses on the aperture blades or blade housing.
If you start out with new lube in the helical at least you have a fighting chance.

Nikon Lenses not stopping down

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