DIY: fixing tight focus ring

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Originally Posted by CGW

Frankly, for a lens that common and cheap, I'd take my chances with a "new" used one.

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Good lord, this is one of the most common lenses on earth. I agree. Just buy another one. That is, unless you like messing with small, delicate parts and want to learn how to do this as an academic exercise.

Its not too bad. I'll do it for you two if you want PM Me.

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Originally Posted by John Koehrer

Gee whiz, I NEVER would have marked the silly thing. That's way too easy. That, by the way was sarcasm.
Now that the pencil and scribed lines have been covered. Why didn't you mention them with your first response to the OP?
Did you assume something like maybe someone who had never taken a lens apart would know they should use witness marks.

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"Be sure you understand what you are doing". I think that covers it. What the hell is your problem?

I found the best grease to be 'vacuum grease' - made for laboratory glassware fittings. It won't outgas (read fog the inside lens surfaces), migrate (read gooey diaphragm) or separate into oil and sludge (read seized focusing helical and an oily diaphragm). My experience with silicon (Silglide), Lithium (Lithease) and Calcium (Lubriplate) greases is that they do all three given a little bit of time.

You can also use 'optical damping grease' but it seems to outgas a wee bit and fog lenses when the grease is new. It is probably a good idea to bake the grease first to get the last of any solvents out of it.

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Originally Posted by Nicholas Lindan

I found the best grease to be 'vacuum grease' - made for laboratory glassware fittings. It won't outgas (read fog the inside lens surfaces), migrate (read gooey diaphragm) or separate into oil and sludge (read seized focusing helical and an oily diaphragm). My experience with silicon (Silglide), Lithium (Lithease) and Calcium (Lubriplate) greases is that they do all three given a little bit of time.

You can also use 'optical damping grease' but it seems to outgas a wee bit and fog lenses when the grease is new. It is probably a good idea to bake the grease first to get the last of any solvents out of it.

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There's a grease called "Krytox" that is designed to not outgass. In my Nikkor lenses, the grease is nowhere near the diaphragm, unless you apply it with a grease gun. Other 35mm lenses may or may not be arranged similarly. I've had no trouble with the lithium grease hazing the glass, but I've only been using it on helicoids for about 13-14 years. The brand I have isn't Lithease, it's an instrument type grease. Again, in my lenses, the helicoid is far enough from the glass that it may not be a problem. I think perhaps the most important thing is, not to apply too much. Some lenses I've had apart are greased up like a wheel bearing.

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Originally Posted by E. von Hoegh

I've had no trouble with the lithium grease hazing the glass, but I've only been using it on helicoids for about 13-14 years.

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That might explain it ... wait a bit longer. OTOH, there are many different lithium greases - Lithease will start to separate in 24 hours. A lot depends on the storage conditions of the lens.

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Originally Posted by Nicholas Lindan

That might explain it ... wait a bit longer. OTOH, there are many different lithium greases - Lithease will start to separate in 24 hours. A lot depends on the storage conditions of the lens.

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The lithium grease I have is a transparent red, it's for intrument use. A friend had a big container and gave me some in a small mustard jar which of course does not have the grease manufacturer's name on it. It doesn't separate at all in the jar, but who knows what time will do to it. The lenses are stored indoors in temperate and dry coditions, but are used in temperatures from -25f to +90f. It gives a very nice low drag but smooth feel to the focussing, which in my opinion is worth cleaning the thing every 20 years or so. :)