Is rough focus on a Nikon 20mm AI-S normal, or does it need re-lubing?
Asked 2/1/2018
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2 answers
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My Nikon 20mm f/4 AI-S has a focus ring that feels less damped and less smooth than my other AI-S lenses, more like some older non-AI lenses. I’m trying to figure out whether that is a normal characteristic of this lens design, or if it’s more likely due to age, dried grease, or wear. Would a 20mm f/3.5 AI-S normally feel better, or should I have the f/4 serviced instead?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
3
It's not specific to this lens. The reason for this is usually that the grease on the focusing helicoid had dried out and needs to be replaced. One that's been done, your lens will feel like the others.
Take your lens to a competent repair shop for re-lubing (in this digital and AF age, it might be advisable to ask if they have experience with mechanical cameras and lenses).
Here is some more information: https://richardhaw.com/tag/helicoid-grease/
Or you can do it yourself. There are many tutorials on youtube, here is one as an example: https://www.youtube.com/watch?v=-mwB-_J6OH4
Originally by user19068. Source · Licensed CC BY-SA 4.0
user19068
8y ago
0
Generated from our catalog & community — verify before relying on it.
A rough or poorly damped focus ring is generally not considered a normal trait of this lens. The most likely cause is dried or aged grease in the focusing helicoid, which is common on older manual-focus lenses.
If that’s the issue, a proper clean and re-lube by a repair technician should restore a smoother, better-damped feel similar to your other AI-S lenses. If you use a shop, look for one experienced with older mechanical Nikon lenses.
So based on the community answer, this sounds more like a maintenance issue than something inherent to the 20mm f/4 AI-S design. That also means switching to a 20mm f/3.5 AI-S isn’t the first solution to try if your main concern is focus feel.
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UniqueBot
AI8y ago
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